- 1 NCERT Class 10 Science Lab Manual Types of Reactions
- 1.1 NCERT Class 10 Science Lab Manual Experiment 3
- 1.2 NCERT Class 10 Science Lab Manual Viva Voce
- 1.3 NCERT Class 10 Science Lab Manual Practical Based Questions
- 1.4 NCERT Class 10 Science Lab Manual Questions
- 1.5 NCERT Class 10 Science Lab Manual Multiple Choice Questions (MCQs)
- 1.6 NCERT Class 10 Science Lab Manual Questions based on Observational Skills
- 1.7 Science Lab Manual Class 10 Questions based on Reporting and Interpretation Skills
- 1.8 CBSE Class 10 Science Lab Manual Scoring Key With Explanation
|Experiment Name||Types of Reactions|
|Category||Class 10 Science Lab Manual|
NCERT Class 10 Science Lab Manual Types of Reactions
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.
> 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
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.
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.
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.
- 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
Give two examples of combination reaction.
When lead nitrate is mixed with potassium iodide solution, name the compound that is formed and give yellow precipitate.
When lead nitrate and potassium iodide are mixed, it forms lead iodide that is yellow precipitate and the other product is potassium nitrate.
What happens if iron nail is dipped in green-coloured ferrous sulphate solution?
There is no change.
What is blue vitriol and green vitriol?
Blue vitriol is CuSO4.5H20
Green vitriol is FeSO4.7H20.
What is the chemical name and formula of lime?
Calcium oxide, CaO.
Name the type of reaction when blue vitriol, i.e., CuSO4.5H2O is heated.
It is a decomposition reaction.
What is the chemical formula of limestone?
Formula of limestone is CaCO3
FeSO4.7H2O is the formula for ferrous sulphate. What does 7H2O stand for?
7H2O is water of crystallisation, i.e., one molecule of FeSO4 needs seven water molecules to form a crystal.
What is the nature of sulphur dioxide and sulphur trioxide gas?
Both SO2 and SO3 are acidic in nature.
What is the colour of iron and copper metal?
The iron metal is grey in colour and copper metal is reddish-brown in colour.
Give the balanced chemical equation to show the reaction between sodium sulphate and barium chloride.
NCERT Class 10 Science Lab Manual Practical Based Questions
State three types of decomposition reaction.
Three types of decomposition reaction are due to
Barium chloride solution mixes with sodium sulphate solution to form a white precipitate. The precipitate occurs due to which salt.
The white precipitate occurs due to formation of barium sulphate.
What happens when zinc is added to blue colour copper sulphate?
The blue-coloured copper sulphate becomes colourless.
Iron nail is dipped in blue-coloured copper sulphate solution. What are the observations?
Iron nail gets reddish-brown coating and the blue-coloured copper sulphate solution becomes green.
If you add water in lime (CaO), what changes will you observe?
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.
State the condition necessary for displacement reaction.
Displacement reaction is possible only when a more reactive metal displaces the less reactive metal.
Name the colour of the gas formed when lead nitrate is heated.
Brown colour gas of nitrogen dioxide is formed.
What is the chemical formula of lime water? What is it commonly called?
The chemical formula of lime water is Ca(OH)2. Ca(OH)2 is commonly called as slaked lime.
Carbon dioxide gas should be passed through lime water only for a short duration. Explain why?
Less carbon dioxide gas will turn lime water milky but excess of CO2 gas will make it colourless.
What is the chemical obtained when excess CO2 is passed through lime water?
On passing excess of CO2 gas through lime water, calcium bicarbonate (CaHCO3 ) is formed which is soluble in water.
What happens when sodium sulphate and barium chloride solution react together?
Sodium chloride and a white precipitate of barium sulphate are formed.
What do you mean by an aqueous solution?
The solution that is made in water is called as an aqueous solution.
What do you mean by precipitate solution?
When the solution obtained is not soluble in water, then we say precipitate is obtained.
Name the products obtained on decomposition of ferrous sulphate crystals.
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
Why does the colour of copper sulphate change, when an iron nail is dipped in it?
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.
How would you devise the procedure to show that Mg > Fe > Cu in reactivity series?
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.
What is the basic principle involved in this experiment?
The more reactive metal can displace the less reactive metal.
Why the following reaction does take place?
Chlorine is more reactive than iodine, hence it displaces the iodide ions from its aqueous solution and release iodine.
Sodium sulphate and barium chloride are ________ (ionic/covalent) compounds.
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).
immediately, ionic, instantaneous.
What may happen on mixing Pb(NO3)2 and KCl solutions? Predict (you may try to experimentally verify).
The displacement reaction takes place and yellow colour precipitate of lead iodide is formed.
What are the industrial applications of the type of reaction being studied?
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?
8. How many water molecules are present in a crystal of ferrous sulphate molecule?
9. Which of the following is an endothermic reaction?
10. What is the colour of FeSO4.7H2O?
11. What is the colour of CuSO4.5H2O?
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
(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
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:
20. When a cleaned iron nail is placed in copper sulphate solution, the colour of the solution changes to:
(c) pale violet
(d) pale green.
21. When zinc granules are dipped in blue coloured copper sulphate solution, the colour of solution obtained is:
22. In the reaction of sodium sulphate and barium chloride the colour of the precipitate formed is
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:
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.
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.
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