Class 10 Science Lab Manual

pH of Samples Experiment Class 10 Practical Science NCERT

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Science (Chemistry)
Experiment Name	ph of samples
Category	Class 10 Science Lab Manual

The experiment to determine pH of Samples are part of Science Lab Manual for Class 10 CBSE Experiments is designed to help students bridge the gap between theoretical concepts and practical applications through hands-on experiments in Chemistry.

Science Lab Manual Class 10 CBSE pH of Samples Experiment

Determine pH of Samples Class 10 Practical

Chemistry Lab Manual Class 10 Introduction
The chemicals used in lab, has its nature, which can be acidic, basic or neutral. This characteristic of the chemical depends on the release of H⁺or OH^– ions in its aqueous solution.
> Chemicals which releases H⁺ ions are acidic whereas which releases OH^– are basic in nature.

NCERT Solutions for Class 10 Acids Bases and Salts

1. pH: It is the power of H⁺ ions in a solution.

It is defined as the negative logarithm of hydrogen ions in a solution. It is used to determine the strength of aci d/base.
The term pH refers to the “potential of hydrogen ion.”
pH is the negative logarithm of the molarity of H⁺.
PH = – log₁₀ [H⁺]
H⁺ is the concentration of hydrogen ion in the solution.
The pH scale is logarithmic, meaning that an increase or decrease of an integer value changes the concentration by a ten fold. For example, a pH of 3 is ten times more acidic than a pH of 4. Likewise, a pH of 3 is one hundred times more acidic than a pH of 5. Similarly a pH of 11 is ten times more basic than a pH of 10.

2. pH scale: pH is normally measured in a range of 0-14. [Due to mathematical definition and calculation it is possible to get negative pH and pH above 14]

3. Nature of Solution on the basis of pH value
• pH < 7: The solutions having pH value below 7 are acidic in nature. These solutions turn blue litmus red.
• pH = 7: The solutions having pH equal to 7 are neutral in nature. These solutions do not show any colour change of litmus.
• pH > 7: The solutions having pH more than 7 are basic in nature. These solutions turn red litmus blue.

4. Measuring pH: The pH of a solution can be determined using an instrument like pH meter or various indicators which changes their colour accordingly depending upon the nature of test solution.
(i) pH Meter: A calibrated instrument called a pH meter can give the pH upto two decimal places.
• pH meters are calibrated using buffer solutions which have an accurately known pH.
• It measures pH more accurately than indicators.
• Now a days pH sensors are used to measure the pH.

(ii) Indicators: It is a substance that can be used to identify the nature of chemicals due to its colour change.
• The indicator changes its colour when the pH of the solution slightly changes.
• When using indicators, it is best that the solution to be tested is colourless. If the solution has a colour, it could interfere with the indicators colour.
Universal indicator or pH paper gives approximate value of the pH.

NCERT Solutions for Class 10 Chemistry

Types of indicators:
(a) Natural Indicators: Exist in nature and generally extracted from plants like turmeric, rose, hibiscus, juice from grapes, cherries, beets, blueberries, radishes, red cabbage and other vegetables or fruits and petals of some flowers contain compounds that can act as indicators, which changes colour in acid or base or in both.
• Litmus: Litmus is a dye extracted from various species of lichen. Lichens are a symbiotic partnership of two organisms, a fungus and an algae that changes colour in acid and base. Red litmus turns blue in basic and blue litmus turns red in acidic medium.
• Cochineal solutions obtained from cochineal insects are yellow in acidic solution and deep violet in alkaline solution. .

(b) Olfactory indicators: An indicator that changes its smell depending on whether it is mixed with an acidic or basic solution is called an olfactory indicator, e.g., onion, clove oil and vanilla extract.

(c) Synthetic Indicators: These indicators are made artificially from chemicals. Examples:
• Phenolphthalein – It changes its colour in bases (turns red or pink). –
• Methyl orange – It changes its colour in acids (turns red or pink).
• Bromothymol blue – It changes colour around the neutral range (green in neutral, yellow in slightly acidic and blue in slightly basic).
• Problems caused due to use of synthetic indicators are: chemical pollution, availability problems and high cost.
The colour change of these indicators in different medium is given below:

Indicator	Acidic Medium	Basic Medium	Neutral Medium
Blue litmus	Red	Blue	Blue
Red litmus	Red	Blue	Red
Phenolphthalein	Colourless	Pink	Colourless
Methyl orange	Pink	Yellow	Pink

5. Universal Indicator: Universal indicator is a mixed indicator (it contains several different colour-changing substances) and shows a range of colours depending on the pH of the solution. It comes in two forms,.either in a liquid solution of ethanol or in a pH paper that has been soaked in the indicator solution.
• pH paper: It is a blotting paper with universal indicator absorbed in it.
• To test the chemical either take a drop of universal indicator on the white tile and add a drop of liquid under test on it or onto the pH paper.

6. Nature of chemicals used in this experiment:
(a) Hydrochloric acid (HCl):
• Hydrochloric acid occurs as an aqueous solution or as hydrogen chloride gas (anhydrous hydrochloric acid).
• Hydrogen chloride gas is a colourless, non-flammable, corrosive gas with an irritating pungent odour.
• When added to water it dissociates completely to form H⁺ ions and Cl^– ions.

• Its pH range is below 7.
• It is used in making fertilizers, in textile and in rubber industries.
• Colour Produced On Universal Indicator By Dilute Hcl

(b) Ethanoic acid (CH₃COOH):
• It is commonly known as acetic acid and is a weak acid.
• When added in water it dissociates partially to form H⁺ ions and acetate ions CH₃COO^–

• Its pH range is less than 7.
• It is used as preservatives and in making of polymers.

(c) Lemon juice:
• Lemon juice is a natural mineral acid which consists of mixture of acids.
• Its pH is less than 7.

(d) Sodium hydroxide (NaOH):
• It is commonly called caustic soda and is a strong base, corrosive in nature.
• When added in water it dissociates completely to form Na⁺ and OH^– ions.

• Its pH range is above 7.
• It is used in making soaps and detergents.

(e) Sodium Bicarbonate (NaHCO₃):
• It is commonly known as baking soda.
• It is a weak base, on dissolving in water it dissociates partially to form Na⁺ and HCO₃^– ions.

• Its pH range is more than 7.
• It is used in making baking powder.

(f) Water (H₂0):
• It is neutral in nature and has pH 7 (at 25°C).
• It is a weak electrolyte.
• Its ionization is partial. On ionization it dissociates to equal number of H⁺ and OH^– ions.

Extended Learning
> The pH of a substance depends on its temperature if the temperature changes the pH shows variation.
> The pH of water at 25°C is 7.
> If the temperature of water increases its pH is less than 7 but the water is neutral. This is because at higher temperature the water will dissociate more into ions.
> If the temperature of water decreases its pH is more than 7 but the water remains neutral. This is because at lower temperature the water will dissociate less into ions.

pH in living system	pH
Gastric acid	1
Human skin	5.5
Urine	6.0
Neutral H₂O at 37°C	6.81
Blood	7.34-7.45
Pancreatic secretion	8.1
Cerebrospinal fluid	7.3
Saliva	6.0-8.0

pH of some common substances used in daily life.

S.No	Name	pH	Nature
1.	Milk of Magnesia	10	Base
2.	Milk	6.8	Acid
3.	Lemon Juice	2.2	Acid
4.	Tomato Juice	4.2	Acid
5.	Pure Distilled Water	7	Neutral
6.	Coffee	5-6	Acid
7.	Vinegar	3	Acid

Ph Value Experiment Class 10 CBSE

Aim
To find the pH of the following samples by using pH paper/universal indicator.

(a) Dilute hydrochloric acid
(b) Dilute NaOH solution
(c) Dilute ethanoic acid solution
(d) Lemon juice
(e) Water
(f) Dilute sodium bicarbonate solution

Theory

● pH is the measure of the hydrogen ion concentration [H⁺] of a solution.
PH = – log₁₀ [H⁺]
● Acids release H⁺ ions when dissolved in water.
● Bases release OH ions when dissolved in water.

pH scale: pH is normally measured in a range of 0-14. [Due to mathematical definition and calculation it is possible to get negative pH and pH above 14]

If pH < 7 then it is acidic solution.
If pH > 7 then it is basic solution.
If pH = 7 then it is neutral.

● Components of Universal Indicator: Universal indicator consists of a mixture of indicators such that there is a continuous colour change on slight change in pH. Some important constituents of universal indicator are:

• Sodium hydroxide • Thymol blue
• Methyl red • Bromothymol blue
• Phenolphthalein • Propanol

● Acids convert blue litmus paper red. For example, HCl, CH₃COOH, etc.
● Bases convert red litmus paper blue. For example, NaOH, NaHCO₃, etc.
● Neutral solutions have no affect on either blue or red litmus paper.

Materials Required
Six test tubes, six droppers, white tile, pH paper (with coloured chart strip of pH scale) and test tube stand.

Chemicals required: Dilute hydrochloric acid, dilute solution of sodium hydroxide, dilute ethanoic acid, lemon juice, distilled water and dilute solution of sodium bicarbonate.
Procedure
1. Take six test tubes, wash them with distilled water and place them on test tube stand.
2. Mark these test tubes as A, B, C, D, E and F.
3. Take 2 mL each of the above chemicals and add them to the test tubes marked.
Test tube A – add 2 mL of dil. HCI acid Test tube B – add 2 mL of dil. NaOH solution
Test tube C – add 2 mL of dil-. ethanoic acid Test tube D – add 2 mL of lemon juice
Test tube E – add 2 mL of distilled water Test tube F – add 2 mL of dil. sodium bicarbonate solution
4. Take a white tile and place small strips of pH paper on it, mark them as A to F.
5. Take clean droppers rinsed with distilled water.
6. Use each dropper to suck the contents present in the test tubes A to F and pour a drop of each content on marked pH paper respectively.
E.g., the contents of test tube A to be placed on the pH paper with label A.
7. Observe the colour change in the pH paper and match it with the colour pH chart given. Record your observations.
Observations

Test tube	Sample	Colour of pH Paper	Approximate pH	Nature
A	Dil. HCI	Red colour	1	Strong acid
B	Dil. NaOH	Dark blue colour	14	Strong base
C	Dil. CH,COOH	Orange colour	3	Weak acid
D	Lemon juice	Pink colour	2	Weak acid
E	Water	Green colour	7	Neutral
F	Dil. NaHCO₃	Light blue colour	9	Weak base

Conclusion

Test tube	Sample
A	Hydrochloric acid
B	Sodium hydroxide
C	Ethanoic acid
D	Lemon juice
E	Water (distilled)
F	Sodium bicarbonate

Precautions

The test sample solutions should be freshly prepared and the firuit juice samples should also be fresh.
Use clean and rinsed droppers.
Use clean test tubes and mark them carefully.
Rinse the test tubes and droppers with distilled water only.
Use clean tile.

Sources of Error

Be careful while using the dropper, ensure that everytime you use a clean dropper.
Do not use tap water for rinsing, the pH may go wrong.

CBSE Class 10 Science Lab Manual Viva Voce

Question 1:
What does “pH of a solution” mean?
Answer:
pH is defined as negative logarithm of the hydrogen ions concentration in a solution.

Question 2:
Name the scientist who introduced pH.
Answer:
Sorensen.

Question 3:
What is the pH of human blood?
Answer:
pH of human blood is 7.34 – 7.45.

Question 4:
What is the range of pH of human saliva?
Answer:
Range of pH of human saliva is 6.0-8.0.

Question 5:
Define ‘indicator’.
Answer:
It is a chemical which changes its colour when comes in contact with acid or base.

Question 6:
Name two synthetic indicators.
Answer:
Methyl orange and phenolphthalein.

Question 7:
Name two plants used to obtain natural indicators.
Answer:
Red cabbage and hibiscus.

Question 8:
Which method of measuring pH is more accurate?
Answer:
Using pH meter for measuring pH gives more accurate result.

Question 9:
If the water is heated and its temperature is increased to 50°C, what would be the pH of water?
Answer:
At 50°C, the pH of water will be 6.55.

Question 10:
What are the components of universal indicator?
Answer:
Components of universal indicator are thymol blue, methyl red, bromothymol blue, phenolphthalein etc.

Question 11:
What will be the colour of the pH paper if the pH value is 7?
Answer:
The colour of pH paper when pH value is 7 will be green.

Question 12:
What will be the colour of pH paper when hydrochloric acid is added to it?
Answer:
On adding hydrochloric acid, the pH paper will obtain pink or red colour.

Class 10 Chemistry Lab Manual Practical Based Questions:

Question 1:
What are strong acids?
Answer:
Those acids which release a large number of H+ ions are called strong acids.

Question 2:
How is pH paper made?
Answer:
A blotting paper is dipped in a universal indicator. When the paper absorbs the indicator it is allowed to dry.

Question 3:
What is pH scale?
Answer:
The pH scale ranges from 0-14 and is used to measure the strength of acids and bases.

Question 4:
Give the use of pH in daily life.
Answer:
Use of antacid during indigestion, using toothpastes to prevent tooth decay, using baking soda when stung by bee, etc.

Value Based Questions CBSE Class 10 Science Acids Bases and Salts

CBSE Class 10 Chemistry Lab Manual Practical Based Questions

Question 5:
Name two natural indicators.
Answer:
Litmus obtained from lichens and turmeric.

Question 6:
Why is the pH of water 7 at 25°C?
Answer:
pH of water is 7 at 25°C because both H+ ion concentration and OH concentration are about 10-7 mol/dm3.

Question 7:
What is the application of pH?
Answer:
pH is used in medicine, agriculture, oceanography etc.

Question 8:
Name two chemicals which will turn pH paper into blue colour.
Answer:
The pH paper becomes blue when sodium hydroxide and sodium bicarbonate solutions are added to it.

NCERT Science Class 10 Lab Manual Questions

Question 1:
What do you mean by pH?
Answer:
pH is power of hydrogen ion concentration in a solution.

Question 2:
What is the pH of pure water at 25°C (298 K)?
Answer:
The pH of pure water at 25°C is 7.

Question 3:
What according to you should be the pH of dil. HCl and dil. NaOH solutions? Observe and explain your findings.
Answer:
The pH of dil. HC1 is less than 7 because when it is dissolved in water it dissociates to release H⁺ ions.
The pH of dil. NaOH is more than 7 because when it is dissolved in water it dissociates to release OH^– ions.

Question 4:
On opening the soda water bottle the dissolved CO₂ comes out, would the pH of the solution increase or decrease as the gas comes out? Explain your answer either way.
Answer:
Soda water bottle is carbonic acid with CO₂ gas dissolved in it. Its pH is less than 7. But when we open it the CO₂ gas is released out and concentration of acid decreases. Hence, the pH increases.

CBSE Class 10 Science Practicals Multiple Choice Questions (MCQs)

Questions based on Procedural and Manipulative Skills

1. Which one of the following is not required to find the pH of a solution?
(a) pH paper
(b) HCl
(c) Universal indicator
(d) Standard pH value chart.

2. Which one of the following solutions would you use to test the pH of a given sample?
(a)   Blue litmus solution
(b)   Red litmus solution
(c)   Universal indicator solution
(d)   Mixture of red and blue litmus solution.

3. Which of the following is not a component of universal indicator?
(a)Methyl red
(b) Thymol blue
(c) Safranin
(d) Phenolphthalein

4. Which of the following turns pH paper to red?
(a) Milk of magnesia
(b) Baking soda
(c) Oxalic acid solution
(d) NaCl solution.

5. If a pH indicator paper is dipped in a grape juice solution, what will be the possible colour of the pH paper?
(a) Deep red
(b) Blue
(c) Orange
(d) Violet

6. The pH of water at 25°C and at 37°C will be respectively.
(a) 6.8 and 7
(b) 1 and 6.8
(c) 7.8 and 6
(d) 6 and 7.8

7. The nature of tea and coffee is:
(a) acidic
(b) highly acidic
(c) basic
(d) highly basic.

8. If pH of the solution changes from 6 to 4, the solution become:
(a) less basic
(b) less acidic
(c) more acidic
(d) neutral.

9. On adding few drops of milk in water, the pH of this solution will be:
(a) 7
(b) 6.8
(c) 8.4
(d) 10.3

10. The acid present in curd is:
(a) acetic acid
(b) oxalic acid
(c) lactic acid
(d) tartaric acid.

11. Water on ionization dissociates to form:
(a) [H+] and [OH^–] ions
(b) [H₃O⁺] and [OH^–] ions
(c) both (a) and (b) are correct
(d) none of these.

Questions based on Observational Skills

12. Solid sodium bicarbonate was placed on a strip of pH paper. The colour of the strip
(a) turned blue
(b) did not change
(c) turned green and then yellow
(d) turned light pink.

13. The two colours seen on the extreme ends of the pH chart are:
(a) red and blue
(b) red and green
(c) green and blue
(d) orange and green.

14. Solution of sodium bicarbonate was placed on a strip of pH paper. The colour of the strip
(a) turned blue
(b) did not change
(c) turned green and suddenly yellow
(d) turned light pink

15. Observe the following figures and choose the correct option.

(a) pH of I is greater than II and IV.
(b) pH of I is less than 111 and IV.
(c) pH of IV is less than 1, II, III.
(d) pH of IV is the highest.

16. The colours obtained on a pH paper for a highly acidic, basic and neutral solutions respectively are
(a) blue, orange, green
(b) yellow, blue, green
(c) red, blue, green
(d) red. green, blue.

17. A student tests the pH of distilled water using pH paper and observed green colour. After adding a few drops of dilute NaOH solution, the pH was tested again. The colour change now observed would be
(a) blue
(b) green
(c) red
(d) orange.

18. A student was given four unknown colourless samples labelled A, B, C and D. He was asked to testtheirpH with pH paper. He observed the following colour changes:
A   – light green       B   – dark red
C   – light orange   D   – dark blue
The correct sequence of increasing order of pH of sample is:
(a)   A < B < C < D   (b)   A<D<C<B
(c)   C < B < A < D   (d)   B < C < A < D.

19. A student adds a few drops of universal indicator to a dilute solution of sodium bicarbonate taken in a test tube.

Which of the following colours would be observed?
(a) Blue
(b) Green
(c) Mustard
(d) Yellow.

20. A student adds a few drops of universal indicator to a solution of dilute hydrochloric acid in the way shown here. He would observe that the colour of the solution changes from colourless to

(a) red
(b) yellow
(c) violet
(d) green.

21. A person X tested the pH of his saliva immediately after drinking coffee. The pH range he got is:
(a) 2.0-3.0 (b) 13.0-14.0
(c) 8.0-9.0 (d) 6.0-7.0

Questions based on Reporting and Interpretation Skills

22. A drop of liquid sample was put on the pH paper. The colour of the pH paper turned blue. The liquid sample could be that of:
(a) lemon juice
(b) hydrochloric acid
(c) sodium bicarbonate solution
(d) ethanoic acid.

23. A colourless liquid sample was tested with pH paper strip. The colour of the strip changed to green. The colourless liquid is
(a) tap water
(b) sodium bicarbonate solution
(c) lemon juice
(d) hydrochloric acid.

24. The colour of the pH paper strip turned red when it was dipped in a sample. The sample could be of
(a) dilute sodium bicarbonate solution
(b) tap water
(c) dilute sodium hydroxide solution
(d) dilute hydrochloric acid.

25. On introducing a strip of pH paper in 1.0 ml of a given solution, the pH paper changed to light red. The given solution could be of:
(a) sodium hydroxide
(b) sodium bicarbonate
(c) a mixture of sodium hydroxide and sodium bicarbonate
(d) ethanoic acid.

26. On putting a drop of liquid on a pH paper a student observes a small circular patch of blue colour on the pH paper. The liquid is most probably:
(a) R,0
(b) HCl
(c) NaOH
(d) H₂SO₄

27. On introducing a strip of pH paper in 1.0 ml of a given solution the pH paper changed to blue. The given solution could be of:
(a) lemon juice
(b) acid rain
(c) a mixture of sodium hydroxide and sodium bicarbonate
(d) acetic acid

28. A few drops of liquid X were added to distilled water. It was observed that the pH of water decreased. The liquid X is
(a) lemon juice
(b) sugar solution
(c) common salt solution
(d) baking soda solution.

29. A moist litmus paper is introduced in a gas jar containing gas. After sometime, the paper becomes colourless. The gas present in the jar is
(a) hydrogen
(b) carbon dioxide
(c) sulphur dioxide
(d) ammonia.

30. On putting a drop of liquid on a pH paper a student observes a small circular patch of red colour on the pH paper. The liquid is most probably
(a) H₂O
(b) HCl
(c) NaOH
(d) Na₂CO₃

31. A fruit juice is tested for its pH value. What could be the possible pH if the colour is changed to yellow?
(a) Less than 3.5
(b) More than 7.5
(c) 7
(d) Between 5.5 and 6.5.

32. When a pH paper is dipped in a solution, the colour of the pH paper changes to deep red. What will be the possible pH of the solution?
(a) 2
(b) 6
(c) 8
(d) none of these.

33. A student placed a few drops of liquid over a portion of the blue litmus paper as shown here. He observed that the blue litmus paper turned red. The liquid could be:

(a) dilute hydrochloric acid
(b) dilute sodium hydroxide
(c) dilute sodium bicarbonate solution
(d) water.

34. On adding a few drops of universal indicator to three unknown colourless solutions P, Q and R, taken in three test tubes separately, as shown in the figure. A student observed the changes in colour as green in (P), red in (Q) and violet in (R).

The decreasing order of pH of the solution taken is
(a) P > Q > R (b) R > P > Q
(c) Q > P > R (d) R > Q > P.

35. Four students were asked to test the pH of four samples as shown under. Whose result is reported correctly?

Student	Water	Ethanoic acid	HCl	NaOH
(a)	7	1	1	1
(b)	7	3	1	1
(c)	7	1	1	13
(d)	7	3	1	13

36. In an experiment to test the pH, of a given sample using pH paper, four students recorded the following observations. Which statement is incorrect?
Sample taken            pH paper colour turned to
(I) Water                               blue
(II) Dil. HCl                           red
(III) Dil. NaOH                       blue
(IV) Dil. Acetic acid               orange
(a)    I      (b) II        (c) III        (d) IV.

37. What will be the pH of dil. HCl if its concentration is 0.01 M?
(a) 2 (b) 3 (c) 1 (d) 4.

38. What is the pH of dil. NaOH if its concentration is 0.01M?
(a) 2 (b) 10 (c) 12 (d) 14.

39. On opening the soda water bottle what will be the pH of the solution when measured after few minutes?
(a) pH increases
(b) pH decreases
(c) pH remains the same
(d) pH is 7.

40. If the pH paper colour is obtained orange on putting a drop of solution, the solution is:
(a) acidic
(b) highly acidic
(c) basic
(d) highly basic.

Chemistry Practicals CBSE Class 10 Lab Manual Scoring Key With Explanation

1. (b) HCl is not an indicator others are.
2. (c) pH can be tested by Universal indicator and not by litmus solutions.
3. (c) Safranin is used in stains and not in indicators.
4. (c) Acids turn pH paper red.
5. (c) Grape juice is weakly acidic in nature.
6. (b) pH of a sample decreases with increase in temperature.
7. (a) They are acidic in nature.
8. (c) Acids have lower pH.
9. (b) Milk is mild acidic.
10. (c) Milk and curd has lactic acid in it.
11. (c) Water has both the ions as given.
12. (h) In solid no ions are present, the litmus works only with ions which are present in molten or in aqueous solution.
13. (a) The pH paper shows red colour for strong acids and blue colour for strong bases.
14. (a) NaHCO₃ is a strong base.
15. (d) pH of base is above 7 and higher than water or acid.
16. (c) Strong acid is red, neutral solution is green and strong base is blue with pH paper.
17. (a) NaOH is a strong base. Hence, the color of pH paper is blue.
18. (d) The pH increases from acid to base and its color shade is from red to blue.
19. (a) Sodium bicarbonate is a base. Hence, the color observed is blue.
20. (a) Acids turn universal indicator to red.
21. (d) Coffee is slightly acidic in nature.
22. (c) It is base, rest all are acids.
23. (a) Water is neutral and the colour of pH paper for neutral solutions is green.
24. (d) Acids turn pH paper strip red.
25. (d) Rest all are bases. Acids change pH paper red.
26. (c) NaOH is base, and base turns pH paper into blue colour.
27. (c) pH paper is blue in base and rest are acids.
28. (a) Acid has pH range from 0-6. Hence, the pH will decrease with addition of acid in water.
29. (c) Sulphur dioxide has bleaching effect.
30. (b) Only acids turn pH paper red.
31. (d) Yellow colour is given by weak acids which is present in fruits and are edible, the pH range of weak acids is between 5 to 6.
32. (a) Deep red colour is seen at the ends of the pH paper and the pH range is 0-2.
33. (a) Acids turn blue litmus paper red.
34. (b) The pH value is above 7 for basic solutions, 7 for neutral solutions and is below 7 for acidic solutions.
35. (d) The pH value is above 7 for basic solutions, 7 for neutral solutions and is below 7 for acidic solutions.
36. (a) Water is neutral in nature. So, it turns pH paper green in colour.
37. (a) HC1 is a strong acid and pH = -log₁₀[10^-2]= 2.
38. (c) pOH = -log[OH] = -log[0.01] = -log[10^-2]
Now, pH + pOH = 14
⇒ pH= 14-2=12
39. (a) The acidic gas is released out.
40. (a) Orange colour is given by acids.

We hope this CBSE Class 10 Science Lab Manual pH of Samples helps you in your preparation for CBSE Class 10 Board Examination. For any questions pertaining to CBSE Class 10 Science Practicals pH of Samples Material, feel free to leave queries in the comments section.

Watch out for the latest updates on NCERT Books, NCERT Solutions, CBSE Sample Papers, RS Aggarwal Solutions and all resources that we share regularly on CBSETuts.com for K12 Students.

More Resources CBSE Class 10 Lab Manual Practical Skills:

NCERT Class 10 Science Lab Manual

Properties of Acids and Bases Experiment Class 10 Practical Science NCERT

Board	CBSE
Textbook	NCERT Books
Class	Class 10
Subject	Science (Chemistry)
Experiment Name	Properties of Acids and Bases
Category	Class 10 Science Lab Manual

The experiment to determine Properties of Acids and Bases are part of Science Lab Manual for Class 10 CBSE Experiments is designed to help students bridge the gap between theoretical concepts and practical applications through hands-on experiments in Chemistry.

Science Lab Manual Class 10 CBSE Properties of Acids and Bases Experiment

Determine Properties of Acids and Bases Class 10 Practical

Science Lab Manual Class 10 Pdf Download Properties of Acids and Bases

Introduction
Acids

> Acids: Acids are defined as proton donors because they lose H⁺ ions.
> Arrhenius definition for acids: Substances which ionizes in water and releases H⁺ ions.
> All acids have hydrogen ions, in it. For e.g., HC, HNO₃.
> Acids can be categorized depending on the number of H⁺ ions released by it.
> If an acid releases one H⁺ ion, it is called monobasic acid, e.g., HCl, HNO₃, CH₃COOH.
> If an acid releases two H⁺ ions, it is called dibasic acid, e.g., H₂SO₄, H₂CO₃.
> They can also be categorized based on the extent of their splitting into ions, when dissolved in water.
> If an acid dissociates (splits) completely into ions it is called strong acid, e.g., sulphuric acid (H₂SO₄).
> If an acid dissociates partially, it is called a weak acid, e.g., acetic acid and citric acid.
> Acids when dissolved in water release large amount of heat. If water is added to concentrated acid then the heat generated may cause the mixture to splash out and cause bums. Hence to avoid burns acid must be added drop wise into water with constant stirring. So that the heat generated spread over in water.

Acid + Water —> Highly exothermic reaction

NCERT Solutions for Class 10 Acids Bases and Salts

Experimental behaviour of acids
> It turns blue litmus red and shows the pH range less than 7.
> On splitting, the H⁺ ions can be replaced by positive ions like ammonium ions, metals ions and other metal compounds like metal oxide, metal hydroxide, metal carbonate and metal hydrogen carbonate.

Bases

> Arrhenius definition of a base: Substance that releases OH^– ions when dissolved in water.
> When the base dissolves in water it is called an alkali.
> Alkalis can be categorized as strong or weak alkali, based on the extent of their splitting into ions, when dissolved in water.
> If an alkali dissociates (splits) completely into ions it is called strong alkali, e.g., sodium hydroxide.
> If an alkali dissociates partially, it is called a weak alkali, e.g., ammonium hydroxide.

Experimental Behaviour of Bases

It changes red litmus blue. Its pH is more than 7.
> When bases react with metals they do not release hydrogen gas. But few exceptional cases are there. For e.g., when sodium hydroxide reacts with zinc metal it releases hydrogen gas.

Hydrogen gas test: To test the hydrogen gas released in an experiment, bring a burning splinter near the mouth of
the test tube/container from which the hydrogen gas is released. Observation: The splinter burns with the pop sound.

> Carbon dioxide gas test: To test the carbon dioxide gas, allow the gas to pass through freshly prepared lime water.
Observation: The freshly prepared lime water turns milky.

Action of acid and base on indicators:

Indicators	Acidic Solution	Basic Solution	Neutral Solution
Blue litmus	Red	No change	No change
Red litmus	No change	Blue	No change
Methyl orange	Red	Yellow	Orange
Phenolphthalein	Colourless	Red or Pink	Colourless

Neutralisation Reaction: Acids and bases react with each other to produce salt and water.

CBSE Class 10 Science Lab Manual Experiment 2

Aim
To study the properties of acids and bases (dilute HCl and dilute NaOH) by their reaction with
(a) Litmus solution (Blue/Red) (b) Zinc metal (c) Solid sodium carbonate

Theory
Hydrochloric acid
> Chemical formula of hydrochloric acid is HCl.
> When it is dissolved in water; releases H⁺(aq) ions, these H⁺ ions cannot exist alone. Hence, it combines with water to form H₃O⁺ (aq) ions.

> The acidic property is seen due to this H⁺(aq) ions/H₃O⁺ ions.

Properties of hydrochloric acid

> It turns blue litmus solution red.
> Hydrochloric acid reacts with metals to release hydrogen gas.

> Test for H₂ gas: When a burning splinter is brought near the mouth of test tube releasing H₂ gas, it bums with a ‘pop sound’.
> Hydrochloric acid react with sodium carbonate to release CO₂ gas.

> Test for CO₂ gas: When CO₂ gas is allowed to pass through freshly prepared lime water, then the lime water turns milky or when a burning splinter is brought near the mouth of the test tube releasing CO₂ gas then the burning splinter extinguishes.
Sodium hydroxide
> Chemical formula of sodium hydroxide is NaOH.
> When it is dissolved in water releases OH^– ions.

Properties of Sodium hydroxide
> It turns red litmus solution blue.
> Not all bases react with zinc metal to release H₂ gas but sodium hydroxide solution reacts with zinc metal to release hydrogen gas.

> Sodium hydroxide do not react with solid sodium carbonate.

Materials Required
A test tube stand, test tubes, match box, test tube holder, droppers, a bent delivery tube, burner and cork.

Chemicals required: Dilute hydrochloric acid, dilute sodium hydroxide, blue litmus solution, red litmus solution, zinc metal granules or powdered zinc, solid sodium carbonate and freshly prepared lime water.

Procedure
(A) Properties of Hydrochloric Acid

Experiment		Observation	Inference
1.	Litmus Test Take two clean test tubes. Pour 1 mL of dilute HCl solution in each test tube. Pour a drop of blue litmus in one test tube and a drop of red litmus solution in the second test tube.	Blue litmus solution turns red in first test tube. Red litmus solution shows no change in second test tube.	Dil. HCl shows acidic character.
2.	Reaction with Zinc Metal Take 1 mL of dilute HCl in a clean test tube. Add a small piece of zinc metal/ zinc powder in it. Light a matchstick and bring it near the mouth of the test tube, remove the thumb and observe.	Zinc metal reacts with the acid. Test tube becomes warm and pressure is exerted on thumb due to release of a gas. The matchstick bums with a pop sound.	Zinc + dil. HCl → Zinc chloride + Hydrogen gas Zn(s) + 2HCl(aq) → ZnCl₂(aq) + H₂(g) Hydrogen gas always bums with a pop sound when lighted matchstick is introduced in it.
3.	Reaction with Sodium Carbonat Take a clean test tube. Add 2 mL of dilute HCl. Now add lg/pinch of sodium carbonate in it. Immediately close the mouth with cork containing delivery tube. Hold a test tube with lime water at the other end of the delivery tube.	Dilute HCl reacts with sodium carbonate to release a colourless gas. The gas turns lime water milky.	(i) Na₂CO₃ + 2HCl → 2NaCl + H₂0 + CO₂ (ii)Ca(OH)₂+CO₂ → Lime waterCaCO₃ +H₂O White insoluble ppt

(B) Properties of Sodium Hydroxide

Experiment		Observation	Inference
1.	Litmus Test Take two clean test tubes. Pour 1 mL of dilute NaOH in each test tube. Add a drop of blue litmus solution in one test tube and a drop of red litmus solution in the second test tube.	Blue litmus solution shows no change. Red litmus solution changes to blue colour.	Dil. NaOH shows basic character.
2.	Reaction with Zinc Metal Take a clean test tube. Add zinc metal granules/zinc powder in it. Pour 2 mL of NaOH solution in the tube. Hold the test tube with a test tube holder and heat it. Bring a burning matchstick near the mouth of the test tube.	On heating the mixture; reaction begins, colourless gas is evolved. The burning matchstick bums with a ‘pop’ sound.	Zn(s) + 2NaOH(aq) Na₂ZnO₂(aq) + H₂(g) Hydrogen gas always bums with a pop sound.
3.	Reaction with Solid Sodium Carbonate Take a clean test tube. Add 2 mL of NaOH solution in a tube and 1 g of sodium carbonate. Heat the mixture.	No change.	Dil. NaOH doesn’t react with sodium carbonate.

Precaution

Use clean test tubes.
Use very small amount of chemicals.
Handle hydrochloric acid and sodium hydroxide solutions very carefully.
Shake the solutions and reaction mixtures carefully without spilling.
Always carry out the test for hydrogen with a very small volume of gas.
For H₂ gas test, be careful as H₂ catches fire. The flame on test tube can be seen due to H₂ gas.
For lime water test, allow the CO₂ gas to pass through lime water and shake the test tube by placing thumb on the mouth of the tube to get quick result.

Science lab manual class 10 NCERT Viva Voce

Question 1:
Acid X reacts with sodium carbonate. Name the gas formed.
Answer:
The gas formed is CO₂

Question 2:
Name the ion released when alkali (bases) dissolve in water.
Answer:
Bases release OH^– ions when dissolved in water.

Question 3:
Name the metal with which NaOH reacts to release H₂ gas.
Answer:
NaOH reacts with zinc metal to release H₂ gas.

Question 4:
A substance X releases OH^– ions when dissolved in water. What is X?
Answer:
X is a base.

Question 5:
A liquid solution ‘Y’ turns blue litmus solution red. What is ‘ Y’?
Answer:
Y is an acid.

Question 6:
What is the chemical formula of sodium zincate?
Answer:
The chemical formula of sodium zincate is Na₂ZnO₂.

Question 7:
Name the metal which reacts with both acid and base to liberate H₂ gas.
Answer:
Zinc metal reacts with both acid and base to release H₂ gas.

Question 8:
What happens to the colour of zinc granules after it has reacted with dil. HCl?
Answer:
Zinc
granules turns black on reaction with dil. HCl.

NCERT Science lab manual class 10 Solutions for Practical Based Questions

Question 1:
Dry litmus paper does not show any colour change when brought close to dry HCl gas. Why?
Answer:
Acids show the acidic character only when they release H⁺(aq) ions when dissolved in water.

Question 2:
If a wet blue litmus paper is brought closer to the dry HCl gas, what change will you observe and why?
Answer:
The blue litmus paper will turn red. This is because the litmus paper is wet and therefore H⁺ (aq) ions are released by HCI gas.

Question 3:
Why does lime water turn milky when CO₂gas is passed through it?
Answer:
Lime water (Ca(OH)₂) reacts with CO₂ to form white insoluble precipitate (CaCO₃) in water which makes lime water milky.

Question 4:
On passing excess CO₂ through lime water it becomes colourless. Explain.
Answer:
When excess CO₂ gas is passed through lime water, it forms calcium hydrogen carbonate which is soluble in water.

Question 5:
State the difference between alkali and base.
Answer:
Bases turn red litmus blue and all bases are not soluble in water. Those bases which are soluble in water are called alkali.

Question 6:
What are the products formed when NaOH solution reacts with zinc metal?
Answer:
NaOH solution reacts with zinc metal to give sodium zincate and hydrogen gas.

Question 7:
What happens if a burning splinter is brought near CO₂ gas?
Answer:
The burning splinter will extinguish, because carbon dioxide gas does not support combustion.

Question 8:
Why do we use zinc granules for the test in the lab?
Answer:
Zinc granules have increased surface area so that reaction occurs fast.

Question 9:
What is the effect of blue litmus and red litmus solution on HCl solution?
Answer:
Blue litmus solution turns red but there is no change in red litmus solution when HCl solution is added to it.

Question 10:
What type of reaction is seen when zinc is added to HCl solution?
Answer:
On adding zinc to HCl solution, the test tube becomes warm and the reaction is exothermic in nature.

Question 11:
What is the formula of lime and lime water?
Answer:
The chemical formula of lime is CaO and that of lime water is Ca(OH)₂.

Question 12:
If you have phenolphthalein as an indicator, how will you test for acid and base?
Answer:
Phenolphthalein turns red or pink in basic solution and remains colourless in acidic solution.

NCERT Chemistry lab manual class 10 Questions

Question 1:
What will be the colour of a blue litmus paper on bringing it in contact with a drop of dil. NaOH?
Answer:
The blue litmus paper remains blue when it comes in contact with a drop of dil. NaOH.

Question 2:
Explain why hydrogen gas is not collected by the downward displacement of air?
Answer:
Hydrogen gas is lighter than air and it will easily escape in the air. We cannot collect the lighter gas by downward displacement of air.

Question 3:
What will happen to a lighted candle if it is brought near the mouth of a gas jar containing hydrogen gas?
Answer:
The lighted candle will burn with the pop sound.

Question 4:
Which gas is produced when aluminium metal reacts with sodium hydroxide?
Answer:
Hydrogen gas is released when aluminium metal reacts with sodium hydroxide.

Question 5:
Hydrogen gas is neutral to litmus paper. Explain how?
Answer:
The litmus paper tests the acid or base due to the release of H⁺ or OH^– ions in aqueous state. In hydrogen gas, the release of such ions is not seen hence the litmus paper does not show any colour change.

Question 6:
What are the metals (other than Al) which react with alkalies to produce hydrogen gas? What are these metals called?
Answer:
Zinc and lead metal will produce hydrogen gas when they react with alkalies. They are called as amphoteric metals.

Question 7:
What will be the colour of a blue litmus paper on bringing it in contact with a drop of dil. hydrochloric acid?
Answer:
The blue litmus paper turns red when it comes in contact with dil. HCl acid.

Question 8:
Which gas is produced when zinc metal reacts with hydrochloric acid?
Answer:
When zinc metal reacts with hydrochloric acid it releases hydrogen gas.

Question 9:
Which gas is liberated when sodium carbonate reacts with hydrochloric acid?
Answer:
When sodium carbonate reacts with hydrochloric acid, carbon dioxide gas is released. .

Question 10:
What is the utility of the reaction between NaHCO₃ and HCl in daily life situation?
Answer:
The reaction between NaHCO₃ and HCl in daily life situation is used to clean the metal surfaces which has developed the deposits of carbonate and hydrogen carbonates.

Question 11:
How can the deposits of carbonates and hydrogen carbonates on the metal surface be cleaned?
Answer:
The deposits of carbonates and hydrogen carbonates on the metal surface can be cleaned by using hydrochloric acid.

CBSE Class 10 Chemistry Practicals Multiple Choice Questions (MCQs)

Questions based on Procedural and Manipulative Skills

1. A freshly prepared lime water is made with
(a) lime + water
(b) calcium oxide + water
(c) both (a) and (b)
(d) none of these.

2. Lime water is
(a) Calcium oxide
(b) Calcium carbonate
(c) Calcium hydroxide
(d) Calcium bicarbonate.

3. The chemical reaction in which zinc metal reacts with dil. HCl is an example of
(a) combination reaction
(b) decomposition reaction
(c) neutralisation reaction
(d) displacement reaction.

4. The zinc metal commonly used in the laboratory for doing experiments is in the form of
(a) filings
(b) strips
(c) granules
(d) pellets.

5. Sodium carbonate reacts with acids to give
(a) CO₂
(b) SO₂
(C) H₂
(d) O₂.

6. Hydrogen gas is not collected by downward displacement of air because:
(a) it is lighter than air
(b) it is explosive in nature
(c) it bums rapidly
(d) it is heavier than air.

7. Carbon dioxide gas is collected by the upward displacement of air because:
(a) it is lighter than air
(b) it is heavier than air
(c) it extinguishes fire
(d) it burns rapidly.

8. Hydrogen gas does not show any change with the litmus paper because:
(a) it does not react with litmus
(b) it is neither acidic nor basic
(c) both (a) and (b) are correct
(d) both (a) and (b) are incorrect.

9. NaHCO₃ is used as an antacid because:
(a) it neutralizes HCl in our stomach
(b) it dissolves HCl in our stomach
(c) it is acidic in nature
(d) it is neutral in nature.

10. A dull coin which is coated with deposits of carbonates and hydrogen carbonates can be cleaned with:
(a) dil. HCl
(b) acetic acid
(c) vinegar
(d) all of these.

Questions based on Observational Skills

11. When excess carbon dioxide gas is passed through lime water it becomes
(a) milky due to the formation of CaCO₃
(b) milky due to the formation of CaHCO₃
(c) colourless due to the formation of CaCO₃
(d) colourless due to the formation of CaHCO₃

12. The reaction between dilute hydrochloric acid and solid sodium carbonate shows the following:
(a) no change takes place
(b) a loud sound is produced
(c) a brisk effervescence occurs
(d) the solution turns blue.

13. When zinc metal reacts with dilute hydrochloric acid, the gas evolved
(a) supports combustion
(b) turns lime water milky
(c) bums with a pop sound
(d) has a pungent odour.

14. When zinc reacts with dilute hydrochloric acid
(a) the surface of zinc becomes brighter
(b) the surface of zinc becomes black and dull
(c) the metal turns into powder
(d) the reaction mixture turns green.

15. When dilute HCl is added to granulated zinc placed in a test tube, the observation made is:
(a) the surface of the metal turns shining
(b) the reaction mixture turns milky
(c) odour of chlorine is observed
(d) a colourless and odourless gas evolves with bubbles.

16. A student takes some zinc granules in a test tube and adds dilute HC1 to it. He would observe that the colour of the zinc granules changes to:
(a) brown
(b) black
(c) yellow
(d) white.

17. A student added dilute HCl to a test tube containing zinc granules and made following observations.
I. The surface of zinc becomes black
II. A gas evolved which burnt with a pop sound
III. The solution remains colourless.
The correct observations are:
(a) I and II (b) I and III
(c) II and III (d) I, II and III.

18. A student performed an experiment using zinc granules and sodium carbonate with sodium hydroxide and hydrochloric acid under different conditions as shown here:

He would observe that no gas is evolved in the setup:
(a) I (b) II
(c) III (d) IV.

19. A student added dilute HCl to Zn granules taken in a test tube. The correct observation would be:

(a) zinc granules turned green
(b) formation of a precipitate
(c) bubbles of a gas
(d) no change.

20. Which one of the following set-up is the most appropriate for the evolution of hydrogen gas and its identification? [CBSE Delhi 2008]

(a) A (b) B (c) C (d) D.

21. When lighted candle is brought near the mouth of a gas jar containing hydrogen gas
(a) the candle is extinguished
(b) the gas will bum explosively with pop sound
(c) the gas burns and candle extinguishes
(d) none of the above.

22. Aluminium metaf reacts with sodium hydroxide solution and hydrochloric acid:
(a) hydrogen gas is released in both the cases
(b) hydrogen gas is released with dil HCl
(c) hydrogen gas is released with NaOH solution
(d) hydrogen gas is not released in any case.

Questions based on Reporting and Interpretation Skills

23. A substance X when dissolved in water releases OH ions, X is
(a) NaCl
(b) HCl
(c) NaOH
(d) Na₂CO₃.

24. A substance Y when dissolved in water forms H⁺ ions, Y is
(a) NaCl
(b) HCI
(c) NaOH
(d) Na₂CO₃

25. A liquid sample turned red litmus paper blue. This indicates that the liquid sample is
(a) an alcohol
(b) hydrochloric acid
(c) distilled water
(d) sodium hydroxide solution.

26. A metal powder was added to dilute HCl and dilute NaOH solution taken in separate test tubes. On making the contents react in both the test tubes, hydrogen gas was formed in both the cases. The metal used is
(a) Cu (b) Zn (c) Fe (d) Pb.

27. When a white powder was mixed with dilute acid, odourless gas was produced which turned lime water milky. The powder may be
(a) carbonate
(b) bicarbonate
(c) sulphate
(d) carbonate or bicarbonate.

28. When a powder was treated with dilute HC1, a gas was produced and when lighted matchstick is shown to it, the flame was put off and the gas also did not burn. The powder may be:
(a) ZnSO₄ (b) CuSO₄
(c) Na₂CO₃ (d) Na2SO₄.

29. Which of the following will give colourless gas that burns with a pop sound, on reaction with dilute HCl ?
(a) Solid sodium carbonate
(b) Zinc metal
(c) Sodium hydroxide
(d) Sodium bicarbonate.

30. Four students were asked by their teacher to arrange the set-up I-IV as given below and identify the gas evolved in each case, if any.

After observation, they arrived at the following inferences and recorded these in the form of a table given below:

The correct observation and inferences have been recorded by student
(a) A (b) B
(c) C (d) D.

31. Four students studied reactions of zinc and sodium carbonate with dilute HCl acid and dilute NaOH solution and presented their results as follows. The (V) represents evolution of gas whereas (x) represents no reaction.

The right set of observations is that of student:
(a) A (b) B
(c) C (d) D.

32. Four students performed the reactions of dilute HCl acid and a solution of sodium hydroxide with zinc metal and solid sodium carbonate separately. They reported the possible reaction by (V) no reaction by (x). In which of the following sets all observations are correct.

33. When zinc metal reacts with dilute hydrochloric acid, the gas evolved is
(a) carbon dioxide
(b) chlorine
(c) hydrogen
(d) oxygen.

34. When sodium carbonate reacts with hydrochloric acid the gas evolved is:
(a) carbon dioxide
(b) chlorine
(c) hydrogen
(d) oxygen.

35. The metals which react with acid and alkalies to produce hydrogen gas are
(a) Na and K
(b) Zn and Na
(c) Al and K
(d) Zn and Al.

CBSE Class 10 Chemistry Lab Manual – Scoring Key With Explanation

1. (c) Lime is calcium oxide and water reacts with it to form lime water.
2. (c) Lime is calcium oxide and water reacts with it to form calcium hydroxide.
3. (d) Zinc is more reactive than hydrogen and it will displace hydrogen ion.
4. (c) Granules has increased surface area for fast reaction.
5. (a) Carbonates release CO₂ gas when reacted with acids.
6. (b) Hydrogen gas is lighter than air but it is explosive in nature, hence it is not collected by downward displacement of air.
7. (b) Heavy gas does not diffuse fast and stays at urface.
8. (b) Hydrogen is neutral.
9. (a) Reaction of acid and base is a neutralization reaction and forms neutral salt.
10. (d) Acids react with it.
11. (d) Calcium bicarbonate dissolves in water.
12. (c) Carbon dioxide gas is released.
13. (c) Hydrogen gas is evolved and it gives pop sound with the burning splinter.
14. (b) Shiny surface of zinc gets coated with zinc chloride.
15. (d) Hydrogen gas is released which is colourless and odourless.
16. (b) Shiny surface of zinc gets coated with zinc chloride which is dull and black.
17. (d) Zinc gets coated with zinc chloride and turns black, it displaces hydrogen when reacted with acids.
18. (b) Bases do not react with solid sodium carbonate.
19. (c) Zinc metal displaces hydrogen when reacted with acids.
20. (b) The tube kept above the solution will release the gas out.
21. (b) Hydrogen gas is combustible.
22. (a) As Aluminium is amphoteric in nature.
23. (c) Bases release OH^– ions.
24. (b) Acids release hydrogen ions.
25. (d) Bases turn red litmus paper blue and sodium hydroxide solution is base.
26. (b) Zinc is amphoteric as it reacts with both acids and bases to form salt and water.
27. (d) Both carbonates and bicarbonates release CO₂ gas when reacted with acids.
28. (c) It contains carbonates, which release CO₂ gas when reacted with acids.
29. (b) Zinc metal displaces hydrogen when reacted with acids.
30. (c) Carbonates release CO₂ gas when reacted with acids. Zinc metal displaces hydrogen when reacted with acids. Base NaOH does not react with sodium carbonate.
31. (a) Zinc is amphoteric and acid reacts with base.
32. (d) Zinc is amphoteric and acid reacts with base.
33. (c) Zinc metal displaces hydrogen when reacted with acids.
34. (a) Carbonates release CO₂ gas when reacted with acids.
35. (d) Zn, Al and Pb are amphoteric metals.

We hope this CBSE Class 10 Science Lab Manual Properties of Acids and Bases helps you in your preparation for CBSE Class 10 Board Examination. For any questions pertaining to CBSE Class 10 Science Practicals Properties of Acids and Bases Material, feel free to leave queries in the comments section.

Watch out for the latest updates on NCERT Books, NCERT Solutions, CBSE Sample Papers, RS Aggarwal Solutions and all resources that we share regularly on CBSETuts.com for K12 Students.

More Resources CBSE Class 10 Lab Manual Practical Skills:

NCERT Class 10 Science Lab Manual

Cleaning Capacity of Soap in Hard and Soft Water Experiment Class 10 Practical Science NCERT

Board	CBSE
Textbook	NCERT Books
Class	Class 10
Subject	Science
Experiment Name	ph of samples
Category	Class 10 Science Lab Manual

The experiment to determine Cleaning Capacity of Soap in Hard and Soft Water are part of Science Lab Manual for Class 10 CBSE Experiments is designed to help students bridge the gap between theoretical concepts and practical applications through hands-on experiments in Chemistry.

Science Lab Manual Class 10 CBSE Cleaning Capacity of Soap in Hard and Soft Water Experiment

Determine Cleaning Capacity of Soap in Hard and Soft Water Class 10 Practical

Introduction
> Water is used for washing along with the soap. The effectiveness and cleansing action of soap depends on the type of water.
> Soft water: The type of water which produces lather with the soap is called soft water. Washing of clothes is very effective and easy in soft water.
> Hard water: The type of water which does not produce lather with the soap is called hard water. It contains dissolved salts in it. The soap forms scum with hard water and not fit for laundry purpose.

Practical Based Questions for Class 10 Chemistry

Types of Hard Water
> Temporary hard water contains dissolved hydrogen carbonate ions, HCO₃^–, of calcium and magnesium.
> Removal of temporary hardness: When water is heated, these ions decompose (break down) to form carbonate ions, CO₃^2-. The carbonate ions in the boiled water react with dissolved calcium and magnesium ions to form calcium carbonate and magnesium carbonate which is insoluble in water and can be removed by filtration. The residue is the insoluble calcium or magnesium carbonate and the filtrate is the soft water.
> Equations:

> Permanent hard water contains dissolved sulphate ions, (SO₄^2-) and chloride ions (Cl^–) of calcium and magnesium. These do not decompose when heated. The ions remain dissolved and do not react with calcium and magnesium ions so the water stays hard even when boiled.
> Soaps do not produce any lather with hard water.
> Removal of permanent hardness of water: The permanent hardness can be removed by boiling it with washing soda, i.e., sodium carbonate (Na₂CO₃)
> When the hard water is heated with sodium carbonate the double displacement reaction takes place. The insoluble calcium and magnesium carbonates are formed and can be removed by filtration.
> Equations:

> Traditional soaps are ionic compounds which dissolve in water forming a long singly charged hydrocarbon negative ion (anion), which is balanced by a singly charged metal positive ion e.g. Na⁺.
> Soap molecules have a hydrophilic ‘head’ (‘water liking’) and a hydrophobic ‘tail’ (‘water hating’).
> When you shake soap with an oily/greasy material (washing clothes or scrubbing a surface), the oil/grease breaks up into tiny droplets or globules and removed from the surface to which they were attached.
> The long ‘hydrocarbon’ hydrophobic tail of the soap dissolves in the oil or grease globule and the negative head is on the surface of the globules/droplets but in contact with water.
> The long ‘hydrocarbon’ hydrophobic tail can only interact at the molecular level with oil/grease. It is attracted to oil and grease.
> The ‘ionic’ hydrophilic head can only interact with water and forms weak bonds with water.
> Two negative hydrophilic heads cannot interact with each other and tend to repel each other, but strongly interact with water.
> The hydrophobic end takes the oil/grease with it and the hydrophilic end gets washed away with the water carrying its tail which is hydrophobic along with the oil/grease.

Science Lab Manual Class 10 Experiment – 7

Aim
To study the comparative cleaning capacity of a sample of soap in soft and hard water.
Theory
> Soap: It is the sodium or potassium salt of long-chained carboxylic acids.

Cleansing Property of Soap
> Soaps when mixed in water its ionic end dissolves in water but the long chain of carboxylic acid does not dissolve in water but dissolves in oil.
> The soap molecules form structures called ‘micelles’.
> The ionic end is towards the water and the non-ionic end faces towards the oil.
> This forms emulsion in water.

> The soap micelles thus helps.in dissolving the dirt in water and we can wash clothes clean.
> Soft water: The water with no salt in it.
> Hard water: The water with dissolved salt in it. It may be calcium or magnesium salts.
> For cleansing purpose, the foam needs to be produced which depends on free availability of hydrophobic portion of soaps (or alkyl group).
> In soft water, soap shows the cleansing property by forming foam.
> In hard water, hydrophobic end of soap is trapped due to scum or precipitation with the calcium and magnesium salts. This makes the hard water unsuitable for washing.

Materials Required
Two test tubes, test tube stand and measuring cylinder.
Chemical required: Samples of hard and soft water, soap solution and cooking oil.

Procedure (Part A)

1. Take 10 mL of distilled water (soft water) in a test tube. Label it as ‘A’.
2. Take 10 mL of hard water (water from hand-pump, underground water) in another test tube. Label it as ‘B’.
3. In both the test tubes, add few drops of soap solution.
4. Shake the test tubes ‘A’ and ‘B’ vigorously for an equal period of time. Keep them in the test tube stand and record your observations.

Observations
1. In test tube A, soap formed lather or foam.
2. In test tube B, white precipitate was formed with no lather or foam.

Conclusion
Soaps are effective cleaner only in soft water because the soap molecules form lather in soft water. But in case of hard water, the soap molecules do not remain as soap molecules but the ionic end of soap reacts with the salts present in hard water to form curdy white precipitate called scum.

Precautions
1. Use same sample of soap solution for soft water and hard water.
2. Same quantity of soap solution must be added to both the test tubes containing soft water and hard water.
3. The concentration of all test solutions must be same.
4. Shake every test tube for equal number of times and in a similar manner.
Note: If hard water is not available prepare some hard water by dissolving hydrogen carbonate/sulphates/chloride salt of calcium or magnesium in water.

Procedure (Part B)

1. Take 10 mL of distilled water/soft water and add a drop of cooking oil in it. Label this test tube as ‘A’.
2. Take 10 mL of hard water and add a drop of cooking oil in it. Label this test tube as ‘B’.
3. Now, add a few drops of soap solution in both the test tubes ‘A’ and ‘B’.
4. Shake both the test tubes vigorously for the same period of time.
5. Keep them on the test tube stand and record your observations.

Observations
1. The test tube ‘A’ with soft water showed the oil emulsified due to soap solution.
2. The test tube ‘B’ showed no emulsification due to soap solution.

Conclusion
1. The formation of emulsion of oil in soft water by soap shows the effect of soap in cleaning.
2. Soaps are more effective cleaners in soft water than in hard water.

Precautions
1. Use same sample of soap solution for soft water and hard water.
2. Use same cooking oil for soft water and hard water.
3. The concentration of all test solutions must be same.
4. Shake every test tube for equal number of times and in a similar manner.

NCERT Class 10 Science Lab Manual Viva Voce

Question 1:
What is hard water?
Answer:
Water with salts in it is called hard water.

Question 2:
Name two sources of soft water.
Answer:
Rainwater, boiled water.

Question 3:
What is a micelle?
Answer:

When soap molecules are dissolved in water they form an arrangement as shown which is called micelle formation.
The ionic end is pointing outside towards water and non-ionic end is pointing towards the oil.

Question 4:
Name the cleansing agent that can be used in hard water.
Answer:
Detergents.

Question 5:
Would you be able to check if water is hard by using a detergent?
Answer:
No, we cannot test for water if it is hard on using a detergent.

NCERT Class 10 Science Lab Manual Practical Based Questions

Question 1:
Name any two salts present in water.
Answer:
Magnesium sulphate and sodium chloride.

Question 2:
Name two sources of hard water.
Answer:
Groundwater, sea.

Question 3:
Why don’t soaps show cleansing property in hard water?
Answer:
It is because soap’s ionic part combines with salts present in hard water to form insoluble precipitate.

Question 4:
Name two parts of a soap molecule.
Answer:
Soap molecule has two parts, i.e., ionic and non-ionic. The ionic part of soap is hydrophilic and non-ionic part is hydrophobic.

Question 5:
Name few dissolved salts present in hard water.
Answer:
The salts that may be present in hard water are hydrogen carbonates, sulphates, chlorides of calcium or magnesium.

Question 6:
What happens when soap solution is mixed with hard water? Why?
Answer:
Soap forms curdy white precipitate when dissolved in hard water. This is because the ionic end of soap molecule on dissolving in water reacts with the salts of hard water to form the precipitate.

Question 7:
Why are soaps effective in soft water and not in hard water?
Answer:
In hard water it forms insoluble precipitate called scum whereas in soft water it does not form any such compound and hence shows its cleansing property.

Question 8:
How will you test in the laboratory, whether the given sample of water is hard or soft? Name two salts which make the water hard. [Delhi 2011]
Answer:
When few drops of soap solution are added in the given sample of water, if lather is formed with soap then water is soft water. If lather is not formed then water is hard. Calcium chloride and magnesium sulphate salts present in water make the water hard.

Question 9:
Can we test hard water by using detergent? Write one more method other than using soap to test the hardness of hard water. [Delhi 2012]
Answer:
We cannot use detergent for testing hard water. As detergents form lather in both hard water and soft water.
Method to test the hardness of water: If on boiling the water, some insoluble salt’s precipitates (white ppt.) are formed, these precipitates then settl e down and can be removed by filtering the water. The given sample of water is then hard water.

Question 10:
When boilers of water are used for a very long time, then white layers get deposited on inside of these boilers?
How can these white layers be removed? [Outside Delhi 2012]
Answer:
When hard water is used in these boilers, then white scum of salts present in the hard water gets deposited inside the boilers making a white layer. These white layers can be removed by washing the boilers with dil. HCl acid.

Question 11:
Name two salts each of calcium and magnesium which make the water hard. [Outside Delhi 2013]
Answer:
These salts are:
Calcium chloride — CaCl₂ Magnesium chloride — MgCl,
Calcium sulphate — CaSO₄ Magnesium sulphate — MgSO₄.

NCERT Class 10 Science Lab Manual Questions

Question 1:
Do both hard water and soft water produces foam with soap?
Answer:
Only soft water produces foam with soap and hard water does not produce any foam.

Question 2:
Why is scum formed when hard water is treated with soap?
Answer:
Hard water contains calcium and magnesium ions in it which reacts with soap to form insoluble precipitate called scum.

Question 3:
What do you understand by temporary and permanent hardness of water?
Answer:
Temporary hardness of water is due to the presence of calcium and magnesium bicarbonate salt dissolved in water. These salts can be removed by a simple process of boiling the water or on addition of sodium carbonate to hard water.
Permanent hardness of water is due to the presence of chloride and sulphate salts of calcium and magnesium in water. These salts cannot be easily removed and needs ion exchange method for removal.

Question 4:
What is the reaction between soap molecules and ions present in hard water?
Answer:

Questions based on Procedural and Manipulative Skills

1. The correct formula for soap is
(a) C₁₇H₃₅COO⁺-Na^–
(b) C₁₇H₃₅COO^–Na⁺
(c) Both (a) and (b)
(d) None of these

2. A student wanted to make hard water in lab, the correct method of doing so is
(a) Water + Magnesium sulphate and sodium chloride
(b) Water + Magnesium chloride and sodium chloride
(c) Water + Magnesium bicarbonate and sodium bicarbonate
(d) All of the above

3. Hardness of water cannot be detected when we add:
(a) soap
(b) detergent
(c) both (a) and (b)
(d) none of these.

Questions based on Observational Skills

4. The micelle of soap is formed on adding soap to water. What is the correct labelling of this micelle?

(a) (1) hydrophobic end (2) hydrophilic end (3) soap
(b) (1) oil (2) hydrophilic end (3) soap
(c) (1) hydrophilic end (2) hydrophobic end (3) oil
(d) (1) hydrophobic end (2) hydrophilic end (3) oil

5. Soap does not show its cleansing property in
(a) distilled water
(b) mineral water
(c) soft water
(d) salty water

6. Two test tubes P and Q as shown in given figure were used to study the cleansing property of soap. In test tube P foam is formed and in test tube Q scum is formed. The best cleansing property of soap is seen in

7. The correct labelling of test tube A and B when A contains soft water and B contains hard water is:

8. Four test tubes marked as P, Q, R and S, contain solutions of sodium chloride, potassium chloride, calcium chloride and magnesium chloride. On adding soap in it the test tube that gives lather is:
(a) P only (h) Q only
(c) R only (d) both P and Q

9. In the above set-up (Q.8) the scum is formed in:
(a) P (b) R
(c) S (d) R and S

10. Soap solution is added to ethyl alcohol, the correct observation is:
(a) it forms lather.
(b) micelles are formed.
(c) soap dissolves in alcohol.
(d) soap forms scum.

11. A student takes potassium chloride, magnesium sulphate, calcium chloride and calcium sulphate in test tubes A, B, C and D respectively. On adding soap solution to each test tube lather is formed in test tube:
(a) A (b) B
(c) C (d) D

12. If soap is added in hard water which of the .following will not happen?
(a) Scum is formed.
(b) Lather is not formed.
(c) Micelles are formed.
(d) No cleansing action of soap.

13. In hard water, detergent is added. Which of the following observation is true?
(a) Foam is formed.
(b) Cleansing action is seen.
(c) Micelles are formed
(d) All of the above.

14. A student takes about 6 mL of distilled water in four test tubes marked P, Q, R and S. He dissolves sodium sulphate in P, potassium sulphate in Q, calcium sulphate in R and magnesium sulphate in S. After that he adds equal amount of soap solution in each test tube. On shaking these test tubes, he would observe a good amount of lather in the test tubes marked
[All India Delhi 2013]
(a) P and Q (b) Q and R
(c) R and S (d) P and S

Questions based on Reporting and Interpretation Skills

15. The white precipitate that is formed when soap is mixed with hard water is due to
(a) ions in water (b) minerals in water
(c) salts in water (d) acid in water

16. Soap shows its cleansing property due to
(a) micelles formation
(b) lather formation
(c) both (a) and (b)
(d) none of these

17. Soap removes dirt from any surface due to
(a) its tadpole structure
(b) mixture formation
(c) lather formation
(d) hydrophobic and hydrophilic ends

18. Two students A and B were told to test for hard and soft water. They both were given test tubes with soft and hard water respectively and few drops of oil in them. Both the students added soap solution in it and recorded their observations. The correct record is

19. The foaming capacity of soap depends on:
(a) hydrophilic part
(b) saponification
(c) ions present in water
(d) alkyl group.

20. The hardness of water is due to
(a) calcium and magnesium ions
(b) sodium and chloride ions
(c) carbonate and biocarbonate
(d) alkyl group.

21. To remove the temporary hardness of water, we can:
(a) add sodium carbonate to it
(b) add sodium hydroxide to it
(c) filter it
(d) boil it.

22. Hard water required for an experiment is not available in a school laboratory. However, following salts are available in the laboratory. Select the salts which may be dissolved in water to make it hard for the experiment. [Delhi 2013]
1. Calcium Sulphate
2. Sodium Sulphate
3. Calcium Chloride
4. Potassium Sulphate
5. Sodium Hydrogen Carbonate
6. Magnesium Chloride
(a) 1,2 and 4 (c) 3, 5 and 6 (b) 1,3 and 6 (d) 2, 4 and 5

23. In a locality, hard water, required for an experiment, is not available. However, the following salts are available in the school laboratory: [Outside Delhi 2014]
(1) Sodium sulphate
(2) Calcium sulphate
(3) Magnesium chloride
(4) Sodium chloride
(5) Calcium chloride
(6) Potassium sulphate
Which of the above salts may be dissolved in water to obtain hard water for the experiment?
(a) 2, 3 and 5 (b) 1,2 and 5
(c) 1,2, 4 and 6 (d) 3 and 5 only

We hope this CBSE Class 10 Science Lab Manual for Cleaning Capacity of Soap in Hard and Soft Water helps you in your preparation for CBSE Class 10 Board Examination. For any questions pertaining to CBSE Class 10 Science Practicals Cleaning Capacity of Soap in Hard and Soft Water Material, feel free to leave queries in the comments section.

More Resources CBSE Class 10 Lab Manual Practical Skills:

NCERT Class 10 Science Lab Manual

Types of Reactions Experiment Class 10 Practical Science NCERT

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Science (Chemistry)
Experiment Name	Types of Reactions
Category	Class 10 Science Lab Manual

The experiment to determine Types of Reactions are part of Science Lab Manual for Class 10 CBSE Experiments is designed to help students bridge the gap between theoretical concepts and practical applications through hands-on experiments in Chemistry.

Science Lab Manual Class 10 CBSE Types of Reactions Experiment

Determine Types of Reactions Class 10 Practical

chemistry practical class 10 Types of Reactions Introduction

> Chemical reaction: The reaction in which two or more substances react to form a new product with new properties is called a chemical reaction.
> Chemical reaction shows following properties:

1. The heat is evolved (either absorbed or released), bubbles may be given out, color may change or the pH may change.
2. The reactants react to give a new product. This involves the breaking of old bonds and formation of new bonds between the atoms.
3. The atoms of the reactant, either lose, gain or share electrons to form new compounds.
4. The total mass of the atoms reacting in the reaction is always conserved. The atoms are neither created nor destroyed, its mass and-number remains the same.

Types of chemical reactions: Combination reaction, decomposition reaction, displacement reaction, double displacement reaction, exothermic and endothermic reactions.
> Combination Reaction: When two or more reactants react together chemically to form a single product, the reaction is called combination reaction. The reactants can be two elements, an element and a compound or two compounds.

> Decomposition Reaction: When a compound breaks down to form simpler products, the reaction is called decomposition reaction. Decomposition can occur due to heat, light and electricity.

> Displacement Reaction: Metals have different reactivity, some are more reactive and some are less reactive. When a more reactive metal displaces a less reactive metal from its salt solution, the chemical reaction is called displacement reaction.

> Double Displacement Reaction: When two salt solutions (containing two different metallic ions) react with each other, the less reactive metallic ion is replaced by the more reactive metallic ion. Due to the interchanging of ions two new salts are formed. Such reaction is called double displacement reaction.
If the salt formed in the above reaction is insoluble in water then such reaction is called precipitation reaction.

> Exothermic reaction: In a chemical reaction, when heat is released then it is called exothermic reaction.

> Endothermic reaction: In a chemical reaction when heat is required for the chemical reaction to take place then it is called endothermic reaction.

Extended learning
> SO₂: Sulphur dioxide is a good reductant. In the presence of water, sulphur dioxide is able to decolourize substances. Specifically, it is a useful for bleaching papers and delicate materials such as clothes. Oxygen in the atmosphere reoxidizes the reduced dyes, restoring the colour.
> SO₃: Sulphur trioxide will cause serious bums on both inhalation and ingestion since it is highly corrosive in nature. SO₃ should be handled with extreme care as it reacts with water violently and produces highly corrosive sulphuric acid.

NCERT Class 10 Science Lab Manual Experiment 3

Aim
To perform and observe the following reactions and classify them into:
(a) Combination reaction (b) Decomposition reaction
(c) Displacement reaction (d) Double displacement reaction.

1. Action of water on quick lime.
2. Action of heat on ferrous sulphate crystals.
3. Iron nails kept in copper sulphate solution.
4. Reaction between sodium sulphate and barium chloride solutions.

Theory
Action of water on quick time
> Quick lime is calcium oxide (CaO). It combines with water to form calcium hydroxide [Ca(OH)₂] also called as slaked lime.

> Two substances are combining to form one product, hence it is a combination reaction.
> Heat is released in the reaction, hence it is called as exothermic reaction.
> Slaked lime solution turns red litmus blue, hence it is basic in nature.
> The freshly prepared slaked lime is also called as lime water.
> It turns milky when carbon dioxide gas is passed through it.

Action of heat on ferrous sulphate crystals
> Ferrous sulphate crystals are light green in colour. The colour is due to the water of crystallization.
> On heating the crystals of ferrous sulphate, it undergoes following changes:

> The colour changes to brown and gases are released due to the formation of new compounds.
> Single compound decomposes to form three new compounds, hence it is called as decomposition reaction.
> SO₂ and SO₃ gas turns moist blue litmus paper into red, hence it is acidic in nature.
> SO₂ shows reducing property: It changes the orange colour of acidified potassium dichromate to green when SO₂ gas is allowed to pass through it.
> Water of crystallisation is released by the crystals.
> SO₂ gas has choking smell, do not inhale the gas, keep the mouth of the test tube away from your face.
Iron nails kept in copper sulphate solution

> Iron nails when kept in blue coloured solution of copper sulphate, shows following changes:
(a) The blue colour solution changes slowly into light green colour.
(b) Fe²⁺ ions replace Cu²⁺ ions and form iron sulphate in the solution, hence, this is called as displacement reaction.
(c) Iron nail gets the deposit of reddish copper ions on it.
(d) Fe atom forms Fe²⁺ ions by loss of electrons and undergoes oxidation and Cu²⁺ ions gain electrons to become Cu atom and undergoes reduction.

Reaction between sodium sulphate and barium chloride solutions

> Sodium sulphate solution and barium chloride solution are colourless.
> Mixing of both the solutions gives white colour precipitate due to the formation of barium sulphate
> The exchange of ions takes place in the reaction and is called as double displacement reaction.
> Barium sulphate is insoluble in water and hence it forms precipitate.

Materials Required
A beaker, four test tubes, test tube holder, tongs, test tube stand, a dropper, a piece of sand paper and bunsen burner. Chemicals required: A small piece of quick lime, ferrous sulphate crystals, iron nails (clean and unrusted), copper sulphate solution, sodium sulphate solution, barium chloride solution and distilled water.

Precautions

Do not touch quick lime with hands, use tongs.
Mixing of quick lime and water releases large amount of heat, so add water drop by drop and use borosil beaker.
For heating, use hard glass tubes.
Never inhale any gas, just waft the gas.
Do not touch any chemical with hands.
Keep the mouth of the test tube away from your face while heating.
The iron nails must be cleaned properly by using sand paper before dipping them in copper sulphate solution.

NCERT Class 10 Science Lab Manual Viva Voce

Question 1:
Give two examples of combination reaction.

Question 2:
When lead nitrate is mixed with potassium iodide solution, name the compound that is formed and give yellow precipitate.
Answer:
When lead nitrate and potassium iodide are mixed, it forms lead iodide that is yellow precipitate and the other product is potassium nitrate.

Question 3:
What happens if iron nail is dipped in green-coloured ferrous sulphate solution?
Answer:
There is no change.

Question 4:
What is blue vitriol and green vitriol?
Answer:
Blue vitriol is CuSO₄.5H₂0
Green vitriol is FeSO₄.7H₂0.

Question 5:
What is the chemical name and formula of lime?
Answer:
Calcium oxide, CaO.

Question 6:
Name the type of reaction when blue vitriol, i.e., CuSO₄.5H₂O is heated.
Answer:
It is a decomposition reaction.

Question 7:
What is the chemical formula of limestone?
Answer:
Formula of limestone is CaCO₃

Question 8:
FeSO₄.7H₂O is the formula for ferrous sulphate. What does 7H₂O stand for?
Answer:
7H₂O is water of crystallisation, i.e., one molecule of FeSO₄ needs seven water molecules to form a crystal.

Question 9:
What is the nature of sulphur dioxide and sulphur trioxide gas?
Answer:
Both SO₂ and SO₃ are acidic in nature.

Question 10:
What is the colour of iron and copper metal?
Answer:
The iron metal is grey in colour and copper metal is reddish-brown in colour.

Question 11:
Give the balanced chemical equation to show the reaction between sodium sulphate and barium chloride.
Answer:

NCERT Class 10 Science Lab Manual Practical Based Questions

Question 1:
State three types of decomposition reaction.
Answer:
Three types of decomposition reaction are due to

Question 2:
Barium chloride solution mixes with sodium sulphate solution to form a white precipitate. The precipitate occurs due to which salt.
Answer:
The white precipitate occurs due to formation of barium sulphate.

Question 3:
What happens when zinc is added to blue colour copper sulphate?
Answer:
The blue-coloured copper sulphate becomes colourless.

Question 4:
Iron nail is dipped in blue-coloured copper sulphate solution. What are the observations?
Answer:
Iron nail gets reddish-brown coating and the blue-coloured copper sulphate solution becomes green.

Question 5:
If you add water in lime (CaO), what changes will you observe?
Answer:
The reaction between lime (CaO) and water is highly exothermic. Large amount of heat is released with the formation of Ca(OH)₂ slaked lime.

Question 6:
State the condition necessary for displacement reaction.
Answer:
Displacement reaction is possible only when a more reactive metal displaces the less reactive metal.

Question 7:
Name the colour of the gas formed when lead nitrate is heated.
Answer:
Brown colour gas of nitrogen dioxide is formed.

Question 8:
What is the chemical formula of lime water? What is it commonly called?
Answer:
The chemical formula of lime water is Ca(OH)₂. Ca(OH)₂ is commonly called as slaked lime.

Question 9:
Carbon dioxide gas should be passed through lime water only for a short duration. Explain why?
Answer:
Less carbon dioxide gas will turn lime water milky but excess of CO₂ gas will make it colourless.

Question 10:
What is the chemical obtained when excess CO₂ is passed through lime water?
Answer:
On passing excess of CO₂ gas through lime water, calcium bicarbonate (CaHCO₃) is formed which is soluble in water.

Question 11:
What happens when sodium sulphate and barium chloride solution react together?
Answer:
Sodium chloride and a white precipitate of barium sulphate are formed.

Question 12:
What do you mean by an aqueous solution?
Answer:
The solution that is made in water is called as an aqueous solution.

Question 13:
What do you mean by precipitate solution?
Answer:
When the solution obtained is not soluble in water, then we say precipitate is obtained.

Question 14:
Name the products obtained on decomposition of ferrous sulphate crystals.
Answer:
On decomposition of ferrous sulphate crystals, the products obtained are Fe₂O₃, SO₂, SO₃ and 14H₂0, i.e., Iron oxide, sulphur dioxide, sulphur trioxide and water.

NCERT Class 10 Science Lab Manual Questions

Question 1:
Why does the colour of copper sulphate change, when an iron nail is dipped in it?
Answer:
On adding iron nail in copper sulphate the displacement reaction takes place. Iron being more reactive than copper displaces copper to form green solution of iron sulphate and copper (pinkish brown) metal is displaced.

Question 2:
How would you devise the procedure to show that Mg > Fe > Cu in reactivity series?
Answer:
Step 1: Add Mg metal in ferrous sulphate, taken in one test tube and to copper sulphate taken in another test tube, wait for some time and note the observations.
Step 2: Add Fe metal in magnesium sulphate taken in one test tube and to copper sulphate taken in another test tube, wait for some time and record the observations.
Step 3: Add Cu metal in a test tube with magnesium sulphate and to other test tube with ferrous sulphate in it. Observe and record.
You will note that magnesium can displace Fe and Cu from their salt solutions, Fe can displace only copper from its salt solution and Cu cannot displace any of the metals from the salt solutions.
Hence, the reactivity can be checked and proved that Mg is the most reactive metal and copper is the least reactive metal among Mg, Fe and Cu.

Question 3:
What is the basic principle involved in this experiment?
Answer:
The more reactive metal can displace the less reactive metal.

Question 4:
Why the following reaction does take place?

Answer:
Chlorine is more reactive than iodine, hence it displaces the iodide ions from its aqueous solution and release iodine.

Question 5:
Sodium sulphate and barium chloride are ________ (ionic/covalent) compounds.
Answer:
Ionic.

Question 6:
As the white precipitate of barium sulphate is formed ___________ (immediately/sometime after mixing
the two solutions), the reaction between ___________ (ionic/covalent) compounds is ___________ (instantaneous/slow).
Answer:
immediately, ionic, instantaneous.

Question 7:
What may happen on mixing Pb(NO₃)₂ and KCl solutions? Predict (you may try to experimentally verify).
Answer:
The displacement reaction takes place and yellow colour precipitate of lead iodide is formed.

Question 8:
What are the industrial applications of the type of reaction being studied?
Answer:
These reactions are used in the extraction of metals in industries. These reactions are also helpful in packaging, food processing industries.

NCERT Class 10 Science Lab Manual Multiple Choice Questions (MCQs)

Questions based on Procedural and Manipulative Skills

1. The addition of water in lime is
(a) endothermic reaction
(b) decomposition reaction
(c) exothermic reaction
(d) displacement reaction.

2. The compound also known as blue vitriol is

3. The chemical formula for lime is

4. The chemical formula for slaked lime is

5. The chemical formula of lead nitrate is:

6. The reaction of water and quick lime is an example of
(a) combination reaction
(b) exothermic reaction
(c) both (a) and (b)
(d) none of these.

7. How many water molecules are present in a crystal of copper sulphate molecule?
(a) 5
(b) 7
(c) 2
(d) 3.

8. How many water molecules are present in a crystal of ferrous sulphate molecule?
(a) 5
(b) 2
(c) 7
(d) 10.

9. Which of the following is an endothermic reaction?

10. What is the colour of FeSO₄.7H₂O?
(a) blue
(b) green
(c) white
(d) brown.

11. What is the colour of CuSO₄.5H₂O?
(a) blue
(b) green
(c) white
(d) yellow.

12. Four students used different ways of burning magnesium ribbon during an experiment as shown below.
The correct way has been followed by student:

NCERT Class 10 Science Lab Manual Questions based on Observational Skills

13. The copper coin is dipped in blue coloured copper sulphate solution, the colour obtained after half an hour is
(a) reddish
(b) brownish
(c) colourless
(d) blue colour.

14. When iron nail js kept in blue coloured copper sulphate solution, after a while the colour obtained in the test tube for the solution is
(a) blue
(b) brown
(c) green
(d) red.

15. On adding zinc granules to freshly prepared ferrous sulphate solution a student observes that:
(a) a dull brown coating is formed
(b) a black coating is formed
(c) a greyish coating is formed
(d) no coating is formed.

16. A student strongly heats hydrated ferrous sulphate salt in a dry test tube. He would observe a:
(a) yellow residue
(b) brown residue
(c) light green residue
(d) white residue

17. A student while heating solid lead nitrate taken in a test tube would observe:
(a) white residue of PbO₂
(b) green residue of NO₂
(c) yellow residue of PbO
(d) brown residue of NO.

18. A student took solid quick lime in a china dish and added a small amount of water. He heard:
(a) a popping sound
(b) a crackling sound
(c) a hissing sound
(d) no sound at all.

19. The colour of the gas evolved on heating solid lead nitrate is:
(a) yellow
(b) brown
(c) greenish-yellow
(d) green.

20. When a cleaned iron nail is placed in copper sulphate solution, the colour of the solution changes to:
(a) blue
(b) red
(c) pale violet
(d) pale green.

21. When zinc granules are dipped in blue coloured copper sulphate solution, the colour of solution obtained is:
(a) blue
(b) yellow
(c) colourless
(d) brown.

22. In the reaction of sodium sulphate and barium chloride the colour of the precipitate formed is
(a) yellow
(b) green
(c) white
(d) black.

23. An iron nail was dipped in a salt solution. After sometime a reddish brown deposition of the nail was seen. The salt solution could be
(a) Silver nitrate
(b) Sodium sulphate
(c) Aluminium chloride
(d) Copper sulphate

24. The colour of the residue left in the test tube after heating ferrous sulphate which undergoes decomposition is:
(a) yellowish-brown
(b) black
(c) white
(d) grey.

25. When ferrous sulphate is heated strongly name the gas evolved?

26. On heating ferrous sulphate one would get
(a) sweet smell
(b) rotten egg smell
(c) irritating choking smell
(d) none of the above

Science Lab Manual Class 10 Questions based on Reporting and Interpretation Skills

27. On adding water to lime we get:

28. On passing CO₂ gas through slaked lime we get

29. On strong heating of ferrous sulphate crystals the products formed are:

30. Magnesium metal burns in air with dazzling white flame. The type of chemical reaction seen is
(a) combination reaction
(b) decomposition reaction
(c) displacement reaction
(d) double decomposition.

31. The reaction of sodium sulphate and barium chloride produces a precipitate, the product formed that gives ppt. is
(a) sodium chloride
(b) barium sulphate
(c) barium sulphide
(d) none of these.

CBSE Class 10 Science Lab Manual Scoring Key With Explanation

1. (c) Lime is calcium oxide and it releases heat when reacted with water.
2. (b) Copper sulphate crystals are blue in colour.
3. (c) Lime is calcium oxide.
4. (a) Slaked lime is calcium hydroxide.
5. (d) The valency of lead is 2 and nitrate ion is 1.
6. (c) Calcium oxide combines with water to form calcium hydroxide and heat is released.
7. (a) It is water of crystallization which is constant for each salt.
8. (c) It is water of crystallization which is constant for each salt.
9. (a) Heat is used for the reaction to occur.
10. (b) Ferrous salts are green in colour.
11. (a) Copper salts are blue in colour.
12. (c) Magnesium ribbon is to be burnt directly on the burner using tongs.
13. (d) Blue colour remains the same as copper and copper salt solution shows equilibrium.
14. (c) Fe is more reactive than Cu and can displace it.
15. (c) Zinc will displace Fe from its solution. The colour of Fe is greyish-black.
16. (b) FeO is formed which is brown in colour.
17. (c) Lead nitrate decomposes to form lead oxide which is yellow in colour.
18. (b) Highly exothermic reaction has occurred.
19. (b) Nitrogen dioxide gas is released which is brown in colour.
20. (d) Iron will displace Cu to form green colour iron sulphate.
21. (c) Zinc will displace Cu from copper sulphate solution and zinc salt solutions are colourless.
22. (c) Barium sulphate is white precipitate.
23. (d) The salt solution should be copper sulphate (CuSO₄). Iron displaces copper from its salt solution as a result of which a reddish-brown layer of Cu is deposited on iron nail.
24. (a) Iron oxide is formed which is brownish in colour.
25.
26. (c) It is a decomposition reaction in which SO₂ and SO₃ are liberated which are choking.
27. (a) Calcium oxide reacts with water to form calcium hydroxide.
28. (a) Calcium hydroxide reacts with CO₂ to form calcium carbonate.
29. (d) Ferrous sulphate crystals decomposes to form these products.
30. (a) Mg bums in air to combine with oxygen and forms MgO.
31. (b) Double displacement reaction is seen.

We hope this CBSE Class 10 Science Lab Manual Types of Reactions helps you in your preparation for CBSE Class 10 Board Examination. For any questions pertaining to CBSE Class 10 Science Practicals Types of Reactions Material, feel free to leave queries in the comments section.

Watch out for the latest updates on NCERT Books, NCERT Solutions, CBSE Sample Papers, RS Aggarwal Solutions and all resources that we share regularly on CBSETuts.com for K12 Students.

More Resources CBSE Class 10 Lab Manual Practical Skills:

NCERT Class 10 Science Lab Manual

Reactivity Series Experiment Class 10 Practical Science NCERT

Board	CBSE
Textbook	NCERT
Class	Class 10
Subject	Science (Chemistry)
Experiment Name	ph of samples
Category	Class 10 Science Lab Manual

The experiment to determine Reactivity Series are part of Science Lab Manual for Class 10 CBSE Experiments is designed to help students bridge the gap between theoretical concepts and practical applications through hands-on experiments in Chemistry.

Science Lab Manual Class 10 CBSE Reactivity Series Experiment

Determine Reactivity Series Class 10 Practical

Reactivity Series Of Metals Class 10 Introduction
Reactivity of elements
> The atoms of the elements in the periodic table react with each other to form new compounds (except noble gases). The atoms react due to its tendency to lose, gain or share electrons.
> Metals: The atoms of metal will always lose electrons to form positive ions called cations. If the atom readily loses electron at room temperature it is said to be reactive metal than the metal whose atom does not readily lose electron at the room temperature.
> Non-Metals: The atoms of non-metals gains or shares electrons to form negative ions called anions, the atoms of non-metals if readily gains electrons it is said to be more reactive.
> Speed of reaction: We can calculate the speed of reaction of metals by allowing them to react with water at room temperature and collect the hydrogen gas obtained. If the temperature of water, the amount of metal and the amount of water is kept constant, the rate of reactivity can be calculated.

Why displacement reaction?
> To arrange the metals in the increasing or decreasing order of their reactivity one of the commonly used experiment is by checking their displacement rate. This is a reliable technique used, because aluminium is actually a reactive metal but due to the protective coating of aluminium oxide on it, the results may show that aluminium’s reactivity rate is slow.
> Hence the displacement reaction is used to arrange the metals in the reactivity series.

Metal Displacement Reactions
> A more reactive metal will displace (take the place of) a less reactive metal in a metal salt solution.

Non-Metal Displacement Reactions
> This is similar to the metal displacement reactions. In case of halogens, more reactive non-metal will displace the less reactive one from its place.

Metal displacement

> For example, in a given chemical reaction:

> Copper (II) sulphate is blue in colour. When iron nail is dipped in this solution, reaction takes place and blue colour disappears and turns greenish and the iron metal gets coated with pink-brown copper metal.
> A more reactive metal will always displace a less reactive metal.
> If a less reactive metal is added to a more reactive metal salt solution then there will be no reaction.
> For example, iron is less reactive than zinc.
Iron + Zinc sulphate —> No reaction.
> In displacement reactions, the metals compete for the non-metal anion. Here, in the above reaction it is S042- ion.
> The order of the metals in the reactivity series can be worked out by using these type of reactions.

Reactivity series
> The arrangement of metals in decreasing order of their reactivity is called reactivity series or activity series of metals.

Mnemonic	Element	Symbol	Reactivity
Put	Potassium	K	As you can see these metals (excluding carbon, as carbon is used for the reduction of metal from metal oxide ore, all metals below carbon are reduced by it) are above hydrogen in the reactivity series so they react with acids and displace hydrogen gas. Metal + Acid —> Metal salt + Hydrogen
Some	Sodium	Na
Light	Lithium	Li
Color	Calcium	Ca
Metal	Magnesium	Mg
Around	Aluminium	Al
Carbon	Carbon	C
Zone	Zinc	Zn
In	Iron	Fe
The	Tin	Sn
Light	Lead	Pb
Here	Hydrogen	H	H⁺ ions are responsible for acidic properties.
Comes	Copper	Cu	These elements are below hydrogen so they do not react with acids. (Acids contain H⁺ ions) Exception: Copper reacts with concentrated nitric acid, the nitrate ions oxidize copper.
Metals	Mercury	Hg
Silver	Silver	Ag
Gold	Gold	Au
Platinum	Platinum	Pt

Note: When metals react with nitric acid they do not release hydrogen gas (except magnesium and manganese) because nitric acid acts as a strong oxidizing agent.

Reactivity Series Class 10 Experiment 4

Aim
(i) To observe the action of Zn, Fe, Cu and Al metals on the following salt solutions:
(a) ZnSO₄(aq.)
(b) FeSO₄(aq.)
(c) CuSO₄ (aq.)
(d) Al₂(SO₄)₃(aq.)
(ii) Arrange Zn, Fe, Cu and Al metals in the decreasing order of reactivity based on the above result.

Theory
> Reactivity series: The arrangement of metals in decreasing order of their reactivity is called reactivity series. The most reactive metal displaces the less reactive metal from its salt solution.

> Metal salts are coloured

> Reaction of Metals with Salt Solution
(i) Salt solution CuSO₄.

As Al, Zn and Fe can displace Cu from its salt solution hence, all three are more reactive than Cu.
(ii) Salt solution FeSO₄.

As Zn and Al can displace Fe from its salt solution hence, Zn and A1 are more reactive than Fe but Cu is less reactive than Fe.
(iii) Salt solution ZnSO₄.

As only Al metal displaces Zn from its salt solution hence, Al is the most reactive metal among Al, Zn, Fe and Cu.
Al > Zn > Fe > Cu.

Materials Required
Four clean test tubes, marker, a piece of sand paper and test tube stand.
Chemicals required: Aluminium sulphate solution, copper sulphate solution, zinc sulphate solution, iron sulphate solution, metal strips of iron, zinc; copper and aluminium.
Procedure
> Reaction with CuSO₄ solution:
1. Take four clean test tubes.
2. With a marker label them as A, B, C and D.
3. Take copper sulphate solution in each test tube.
4. Dip a small, clean piece of aluminium, zinc, iron and copper metals in test tubes A, B, C and D respectively.
5. Record your observations.

Conclusion: Al, Zn and Fe metals are more reactive than Cu. Hence, Cu is the least reactive metal among the given four metals.
> Reaction with FeSO₄ solution:
1. Take four clean test tubes, labelled as A, B, C, and D.
2. Take FeSO₄ (aq) solution in each test tube.
3. Dip small, clean pieces of aluminium, zinc, iron and copper metals in test tube A, B, C and D respectively.
4. Record your observations.

Conclusion: Al and Zn metals are more reactive than Fe and Cu.

> Reaction with ZnSO₄ solution:
1. Take test tubes A, B, C, and D, clean them.
2. Add ZnSO₄ solution in each test tube.
3. Dip small, clean pieces of Al, Zn, Fe and Cu metal in test tube A, B, C and D respectively.
4. Record your observations.

Conclusion: Al metal is more reactive than Zn metal.

> Reaction with Al₂(SO₄)₃solution:
1. Take test tubes A, B, C, and D and clean them.
2. Add Al₂(SO₄)₃solution in each test tube.
3. Dip small, clean pieces of Al, Zn, Fe and Cu metal in test tubes A, B, C and D respectively.
4. Record your observations.

Conclusion: Al metal is not displaced by any of the given metals i.e. Al, Zn, Fe and Cu.

Hence, Al metal is the most reactive metal among the given metals.
1. Al is not displaced by any of the four metals from its salt solution, hence, Al is at the top of the reactivity series.
2. Al can displace Zn from its salt solution but no other metal could displace it. Hence, the reactivity order is Al > Zn.
3. Al and Zn metals can displace Fe metal from its salt solution but Cu cannot.
Hence, the arrangement of metals in decreasing reactivity order is
Al > Zn > Fe > Cu.

I. CuSO₄ solution in each test tube.

II. FeSO₄ solution in each test tube.

III. ZnSO₄ solution in each test tube.

IV. Al₂(SO₄)₃ solution in each test tube.

Precautions
1. Clean the metals by rubbing them with a piece of sand paper before dipping them in the salt solutions.
2. Wash the test tubes after every set of observations of interaction of a particular metal with the four salt solution.
3. Use very little amount of saturated solution of copper sulphate, aluminium sulphate, iron sulphate and zinc sulphate.
4. Use very small pieces of metal every time.
5. Do not touch any chemical.

Viva Voce

Question 1:
What is the colour of copper sulphate solution?
Answer:
The colour of copper sulphate solution is blue.

Question 2:
What is the colour of iron sulphate solution?
Answer:
The colour of iron sulphate solution is green.

Question 3:
When we add Fe in FeSO₄ solution, no change is seen. Why?
Answer:
It is because Fe does not react with FeSO₄ solution.

Question 4:
Name one metal which when added to blue CuSO₄ solution changes it to green colour.
Answer:
Iron metal reacts with blue-coloured copper sulphate solution and changes it into green colour.

Question 5:
What is the colour of Al₂(SO₄)₃ solution?
Answer:
Al₂(SO₄)₃ solution is colourless.

Question 6:
Complete the given chemical equation Fe(s) + CuSO₄(aq) —>
Answer:
Fe(s) + CuSO₄(aq) —> FeSO₄(aq) + Cu(s)

Practical Based Questions

Question 1:
What is the activity series of metals?
Answer:
The arrangement of metals in the decreasing order of their reactivity is called activity series of metals.

Question 2:
What is displacement reaction?
Answer:
When a more reactive metal displaces the less reactive metal from its salt solution, it is called displacement reaction.

Question 3:
What happens when a piece of zinc metal is introduced into a freshly prepared solution of ferrous sulphate?
Answer:
The colour of ferrous sulphate solution is green and when zinc is added to it the colour fades and becomes colourless.

Question 4:
What happens when Fe (Iron) metal is added to blue colour copper sulphate solution?
Answer:
Iron metal reacts with copper sulphate solution to displace copper and form iron sulphate that is green in colour.
Fe(s) + CuSO₄(aq) —> FeSO₄(aq) + Cu(s)

Question 5:
What happens when A1 metal is added to copper sulphate solution?
Answer:
Al metal reacts with copper sulphate solution to form aluminium sulphate and copper metal is displaced.

Question 6:
Name the least reactive metal among the following: Fe, Zn, Al.
Answer:
Fe is the least reactive metal among Fe, Zn, and AT

Question 7:
What will happen if Fe metal is added to ZnSO₄ solution?
Answer:
No reaction will take place, as Fe metal is less reactive than Zn.

Question 8:
Arrange the given metals in the reactivity series:
Mg, Zn, Cu, Fe, Al
Answer:
The reactivity series of metals is
Mg > Al > Zn > Fe > Cu

Question 9:
Name some metals that will react with aluminium sulphate solution, i.e., Al₂(SO₄)₃.
Answer:
Metals like calcium, sodium and magnesium will react with aluminium sulphate solution.

Question 10:
When you keep aluminium strip in FeSO₄ solution, what change is seen?
Answer:
Aluminium is more reactive than Fe hence it displaces Fe from FeS04 and green colour of FeSO₄ disappears.

Question 11:
Why is Fe metal more reactive than copper metal?
Answer:
Fe readily loses electrons as compared to copper. Hence, it is more reactive than copper metal.

Question 12:
How can you test that a given sample contains water or not?
Answer:
On heating copper sulphate crystals the blue colour of copper slowly changes to light blue and then colourless. The water droplets are collected on the inner part of the test tube.

Question 14:
It is regarded that each molecule of copper sulphate crystals at room temperature contains five water molecules as water of crystallisation. Do you see any difference in them? (Hint: Look at the dehydration reaction of copper sulphate)
Answer:
In one molecule of copper sulphate, five water molecules are present to form crystal. The blue colour of the crystals is due to these five water molecules. But, in anhydrous copper sulphate the water molecules are not present.

NCERT Lab Manual Questions

Question 1:
Why does the colour of copper sulphate solution change, when an iron nail is dipped in it?
Answer:
The iron nail reacts with copper sulphate displace copper and form iron sulphate . Due to the displacement reaction the blue colour of copper sulphate changes to green colour of iron sulphate.

Question 2:
How would you devise the procedure to show that Mg > Fe > Cu in reactivity series? What is the basic principle involved in this Experiment?
Answer:
I will react each metal (Mg, Fe and Cu) with the salt solutions of Mg, Fe and Cu. The metal that will displace two metal ions from the salt solutions will be the most reactive and the one which will not show any colour change in the solutions is the least reactive.
Principle: The most reactive metal will displace the less reactive metal.

Question 3:
Why does the following reaction takes place?
2I^–(aq) + Cl₂ (aq) —> 2l^– (aq) + I₂ (solvated)
Answer:
This is the displacement reaction seen among halogens. Chlorine is more reactive than iodine and hence it displaces iodide ion.

Question 4:
In the following reaction, A and B are metals. BX is a salt of metal B.
A + BX —> AX + B
Which one of the two metals is more reactive? Give reason.
Answer:
Metal A is more reactive than B, because metal A displaces metal B from its salt solution.

Question 5:
Name any two metals that are more reactive than iron.
Answer:
Zinc and magnesium.

Question 6:
Why did the colour of copper (II) sulphate solution, change, when zinc metal was dipped in it?
Answer:
Zinc is more reactive than copper and displaces copper from its solution. Hence, the blue colour of copper sulphate solution becomes colourless.

Question 7:
What is your observation when copper is added in iron (II) sulphate solution?
Answer:
Copper is less reactive than iron and cannot displace iron from iron sulphate solution and there is no colour change.

Question 8:
Why can we safely preserve iron (II) sulphate in a copper vessel whereas the same can’t be safely preserved in zinc vessel?
Answer:
Copper is less reactive than iron and cannot react with iron sulphate. Whereas zinc is more reactive than iron and hence it can react with iron sulphate.

Multiple Choice Questions (MCQs)

Questions based on Procedural and Manipulative Skills
1. When an iron strip was placed in the copper sulphate
solution, the time required for the colour of the solution to change from blue to green will be less if:
(a) it is cooled
(b) it is shaken
(c) it is kept undisturbed
(d) it is heated.

2. The colour of zinc sulphate solution is
(a) white
(b) green
(c) yellow
(d) colourless.

3. Which of the following reaction will not occur?
(a) Al + ZnSO₄
(b) Zn + ZnSO₄
(c) Cu + ZnSO₄
(d) Mg + ZnSO₄.

4. Which of the following reaction will take place?
(a) Fe + FeSO₄
(b) Cu + FeSO₄
(c) Au + FeSO₄
(d) Mg + ZnSO₄.

5. To show that zinc is more reactive than copper, the correct procedure is to
(a) prepare copper sulphate solution and dip a zinc strip in it.
(b) prepare copper sulphate solution and dip a copper strip in it.
(c) heat zinc and copper strips.
(d) add dilute nitric acid on both the strips.

6. On adding iron strip in copper sulphate solution, the reaction takes long time, to make it happen fast we can:
(a) add more iron strips
(b) add more copper sulphate solution
(c) heat the container of reactants
(d) heat iron and add in copper sulphate.

7. You are given two test tubes A and B, with solutions ZnS04 and A12(S04)3, both are colourless. To identify the solutions,
(a) add Zn in test tube A and B
(b) add A1 in test tube A and B
(c) first add Zn and then A1 in test tubes A and B
(d) all the above are correct.

8. Two metals which can displace iron from its solution are:
(a) copper and zinc
(b) zinc and tin
(c) silver and aluminium
(d) zinc and aluminium.

9. P + QR → PQ + R. In the above reaction,
(a) Q displaces P
(b) R is displaced by P
(c) P displaces Q
(d) R displaces Q.

10. Two beakers A and B contain Iron (II) sulphate solution. In the beaker A is placed a small piece of copper and in the beaker B is placed a small piece of zinc. It is found that a grey deposit forms on the zinc but not on the copper. From these observations it can be concluded.
(a) Zinc is most active metal followed by iron and copper.
(b) Zinc is most active metal followed by copper and then iron.
(c) Iron is most active metal followed by zinc and then copper.
(d) Iron is most active metal followed by copper and then zinc.

Questions based on Observational Skills

11. A student took Cu, Fe, Zn and Al strips separately in four test tubes labelled I, II, III and IV respectively. He added 10 mL of freshly prepared ferrous sulphate solution to each test tube as shown below:

Black residue would be obtained in test tubes:
(a) I and II (b) I and III
(c) II and III (d) III and IV.

12. Aluminium powder was added to a solution of copper sulphate. The colour of the solution changed from:
(a) colourless to blue
(b) blue to colourless
(c) light green to blue
(d) reddish-brown to light green.

13. The colour of the coating obtained on a zinc rod on dipping in aqueous copper sulphate solution will be
(a) blue (b) brown
(c) white (d) green.

14. Which one is not observed when aluminium is added to a solution of copper sulphate?
(a) The solution is blue in the beginning.
(b) The final solution becomes colourless.
(c) The final solution becomes light green.
(d) A brown mass is deposited on the surface of aluminium.

15. Copper turnings were added to colourless salt solution. After 10 minutes it was observed that the colourless solution turned to a coloured solution and a shiny metal deposition appears. The colour of the solution and that of the metal would respectively be
(a) yellow and Zn (b) green and Fe (c) red and Sn (d) blue and Ag.

16. Iron filings were added to an aqueous solution of copper sulphate. After some time, on observation, it was found that the colour of the solution has changed from
(a) blue to pale green (b) blue to dark green (c) blue to colourless (d) blue to reddish-brown.

17. Zinc granules were added to zinc sulphate, copper sulphate, aluminium sulphate and iron sulphate solutions as shown below. You would observe the deposition of metal on zinc in test tubes

(a) I and III (b) II and IV
(c) I and II (d) III and IV.

18. A student added a piece of zinc metal in four different test tubes containing different solutions. In which test tube he observed no change?
(a) Test tube with CuSO₄ solution
(b) Test tube with AgNO₃ solution
(c) Test tube with ZnSO₄ solution
(d) Test tube with FeSO₄ solution.

19. A student performed the following four experiments:

He would find the formation of solid deposition on
metal in experiments
(a) II, III (b) I, III
(c) I, II, III (d) II, III, IV.

20. A piece of granulated zinc was dropped into copper sulphate solution. After some time, the colour of the solution changed from
(a) light green to blue
(b) blue to colourless
(c) light green to colourless
(d) blue to yellow.

21. A strip of copper was placed in a beaker containing zinc sulphate solution. On observing the strip the next day, it was noticed that
(a) the copper strip remained as it was
(b) the copper strip became thinner
(c) the copper strip became thicker
(d) the colour of the strip changed.

22. When a few crystals of copper sulphate are dissolved
in water, the colour of the solution obtained would be:
(a) green (b) red
(c) blue (d) brown.

23. Iron filings were added to a solution of copper sulphate. After 10 minutes, it was observed that blue colour of the solution changes and a layer gets deposited on iron filings. The colour of the solution and that of the coating would respectively be
(a) yellow and green
(b) brown and blue
(c) red and greenish-blue
(d) green and reddish-brown.

24. Iron spoon was placed in a glass container holding zinc sulphate solution. What is the right observation?
(a) Zinc sulphate will become green.
(b) Glass container will get cracks.
(c) Iron spoon will get holes in it.
(d) Iron spoon will not show any change.

25. When an aluminium strip is kept immersed in freshly prepared ferrous sulphate solution taken in a test tube, the change observed is
(a) the green solution slowly turns blue.
(b) the lower end of the test tube becomes slightly warm.
(c) a colourless gas with a smell of burning sulphur is observed.
(d) light green solution changes to blue.

26. Solutions of FeSO₄, ZnSO₄, CuSO₄ and Al₂(SO₄)₃ solutions were separately taken in four test tubes and some iron nails were placed in each of the solutions. After a few minutes, it would be observed that the colour of
(a) all the four solutions changed.
(b) solution of ZnSO₄, CuSO₄ and Al₂(SO₄)₃ changed and that of FeSO₄ did not change.
(c) solution of ZnSO₄ and Al₂(SO₄)₃ only changed.
(d) copper sulphate solution only changed.

27. When you place iron nail in copper sulphate solution, the reddish brown coating formed on the nail is
(a) soft and dull.
(b) hard and flaky.
(c) smooth and shining
(d) rough and granular.

Questions based on Reporting and Interpretation Skills

28. 10 mL of freshly prepared iron sulphate was taken in
each of four test tubes. Strips of copper, iron, zinc and aluminium were introduced, each metal in a different test tube. A black residue was obtained in two of them.
The right pair of metals forming the precipitates is
(a) Copper and zinc
(b) aluminium and copper
(c) iron and aluminium
(d) zinc and aluminium

29. Four students were assigned separately the experiment of interaction of an iron nail with a solution of copper sulphate. Each group recorded the observations as [ given below in the table. Which group of students recorded the observations correctly?

30. A student took four test tubes containing solutions of different colours marked I, II, III, and IV as shown below. The test tubes containing copper sulphate solution and ferrous sulphate solution could be the tubes:

31. Four students A, B, C and D noted the initial colour of the solutions in test tubes I. II, III and IV. After inserting
zinc rod in each solution and leaving it undisturbed for two hours, they noted the colour of each solution again.

They recorded their observations in the form of table given below:

Students	Colour of solution	I	II	III	IV
A	Initial	Colourless	Colourless	Light green	Blue
A	Final	Colourless	Colourless	Colourless	Colourless
B	Initial	Colourless	Light yellow	Light green	Blue
B	Final	Colourless	Colourless	Light green	Colourless
C	Initial	Colourless	Colourless	Light green	Blue
C	Final	Light blue	Colourless	Colourless	Light blue
D	Initial	Light green	Colourless	Light green	Blue
D	Final	Colourless	Colourless	Dark green	Colourless

Which student noted the colour change in all the four test tubes correctly?
(a) A (b) B (c) C (d) D.

32. Aluminium sulphate and copper sulphate solutions were taken in two test tubes I and II respectively. A few pieces of iron filings were then added to both the solutions. The four students A, B, C and D recorded their observations in the form of a table as given below.

Students	(I) Al₂(SO₄)₃ Solution	(II) Copper Sulphate Solution
A	Colourless solution changes to light green	Blue colour of the solution is retained.
B	Colourless solution remains unchanged	Blue solution changes to green.
C	Colourless solution changes to light blue	Blue colour changes to light green.
D	Colourless solution remains unchanged	Blue colour of the solution fades away.

The correct set of observations have been recorded by student
(a) A (b) B (c) C (d) D.

Scoring Key With Explanaion

1. (d) Heat increases the rate of reaction.
2. (d) Zinc salt solutions are colourless.
3. (c) Cu is less reactive than Zn.
4. (d) Mg is more reactive than Zn.
5. (a) This will show displacement reaction.
6. (c) Increase in temperature speeds up the reaction.
7. (d) All tests will help in identifying the solutions.
8. (d) Both are more reactive than Fe.
9. (b) R is removed from the compound and exists freely.
10. (a) Copper does not react, but zinc reacts with ferrous sulphate solution.
Thus, zinc is more reactive followed by iron and copper.
11. (d) Zn and Al are more reactive than Fe and can displace it.
12. (b) Copper salt is blue in colour and aluminium salts are colourless.
13. (b) Cu is displaced by Zn which is brown in colour.
14. (c) Aluminium salt is colourless and not green in colour.
15. (d) Copper is more reactive than Ag.
16. (a) Fe displaces copper ions.
17. (b) Zinc is more reactive than Cu and Fe.
18. (c) Equilibrium is seen.
19. (c) As per reactivity series.
20. (b) Zinc salt solutions are not coloured.
21. (a) Copper is less reactive than zinc.
22. (c) Cu salt is blue coloured.
23. (d) Ferrous salts are green.
24. (d) Iron is less reactive than Zn.
25. (b) It shows thermite reaction and heat is evolved.
26. (d) Cu is the least reactive metal and can be displaced by all the metals given.
27. (a) The freshly deposited copper is soft and dull.
28. (d) Zinc and alufninium being more reactive will replace iron from iron sulphate.
29. (d) Fe will displace Cu ions to give green colour solution and Cu metal is brown coated.
30. (d) Copper sulphate is blue and ferrous sulphate is green in colour.
31. (a) In first two test tubes, the metal will not react but in other two it will react.
32. (b) Fe is less reactive than Al but more reactive than Cu. Hence, displacement reaction will occur.

We hope this CBSE Class 10 Science Lab Manual Reactivity Series helps you in your preparation for CBSE Class 10 Board Examination. For any questions pertaining to CBSE Class 10 Science Practicals Reactivity Series Material, feel free to leave queries in the comments section.

Watch out for the latest updates on NCERT Books, NCERT Solutions, CBSE Sample Papers, RS Aggarwal Solutions and all resources that we share regularly on CBSETuts.com for K12 Students.

More Resources CBSE Class 10 Lab Manual Practical Skills:

NCERT Class 10 Science Lab Manual

MCQ Questions	NCERT Solutions
CBSE Sample Papers
NCERT Exemplar Solutions	LCM and GCF Calculator
TS Grewal Accountancy Class 12 Solutions
TS Grewal Accountancy Class 11 Solutions

Class 10 Science Lab Manual

Science Lab Manual Class 10 CBSE pH of Samples Experiment

Determine pH of Samples Class 10 Practical

Ph Value Experiment Class 10 CBSE

CBSE Class 10 Science Lab Manual Viva Voce

Class 10 Chemistry Lab Manual Practical Based Questions:

CBSE Class 10 Chemistry Lab Manual Practical Based Questions

NCERT Science Class 10 Lab Manual Questions

CBSE Class 10 Science Practicals Multiple Choice Questions (MCQs)

Chemistry Practicals CBSE Class 10 Lab Manual Scoring Key With Explanation

Science Lab Manual Class 10 CBSE Properties of Acids and Bases Experiment

Determine Properties of Acids and Bases Class 10 Practical

CBSE Class 10 Science Lab Manual Experiment 2

Science lab manual class 10 NCERT Viva Voce

NCERT Science lab manual class 10 Solutions for Practical Based Questions

NCERT Chemistry lab manual class 10 Questions

CBSE Class 10 Chemistry Practicals Multiple Choice Questions (MCQs)

CBSE Class 10 Chemistry Lab Manual – Scoring Key With Explanation

Science Lab Manual Class 10 CBSE Cleaning Capacity of Soap in Hard and Soft Water Experiment

Determine Cleaning Capacity of Soap in Hard and Soft Water Class 10 Practical

Science Lab Manual Class 10 Experiment – 7

NCERT Class 10 Science Lab Manual Viva Voce

NCERT Class 10 Science Lab Manual Practical Based Questions

NCERT Class 10 Science Lab Manual Questions

Science Lab Manual Class 10 CBSE Types of Reactions Experiment

Determine Types of Reactions Class 10 Practical

chemistry practical class 10 Types of Reactions Introduction

NCERT Class 10 Science Lab Manual Experiment 3

NCERT Class 10 Science Lab Manual Viva Voce

NCERT Class 10 Science Lab Manual Practical Based Questions

NCERT Class 10 Science Lab Manual Questions

NCERT Class 10 Science Lab Manual Multiple Choice Questions (MCQs)

NCERT Class 10 Science Lab Manual Questions based on Observational Skills

Science Lab Manual Class 10 Questions based on Reporting and Interpretation Skills

CBSE Class 10 Science Lab Manual Scoring Key With Explanation

Science Lab Manual Class 10 CBSE Reactivity Series Experiment

Determine Reactivity Series Class 10 Practical

Reactivity Series Class 10 Experiment 4

Viva Voce

Practical Based Questions

NCERT Lab Manual Questions

Multiple Choice Questions (MCQs)

Scoring Key With Explanaion

Footer

Maths NCERT Solutions

SCIENCE NCERT SOLUTIONS