- 1 Class 10 Science Chapter 3 Important Questions with Answers Metals and Non-metals
Solved the very best collection of Metals and Non-metals Class 10 Science Important Questions and Answers Chapter 3 Pdf from the latest NCERT edition books, It will help you in scoring more marks in CBSE Exams.
Class 10 Science Chapter 3 Important Questions with Answers Metals and Non-metals
Class 10 Chemistry Chapter 3 Important Questions with Answers Metals and Non-metals
Metals and Non-metals Class 10 Important Questions Very Short Answer Type
Why does a metal not release H2 gas on reacting with dilute nitric acid?
As nitric acid acts as a strong oxidising agent and oxidises the released H2 gas to H2O and itself is reduced to either of these gases – N2O, NO2 or NO.
Why is copper used to make hot water tanks whereas steel is not?
Copper is a better conductor of heat as compared to steel. Therefore, hot water tanks are made of copper.
Why do the non-metals not displace hydrogen from dilute acids?
Non-metals being acceptor of electrons, cannot give electrons to the hydrogen ions of acid to reduce them to hydrogen gas. Hence non-metals do not displace hydrogen from dilute acids.
Give an example of a metal which
(i) can be easily cut with a knife.
(ii) is a liquid at room temperature.
Metals and Non-metals Class 10 Important Questions Short Answer Type I
Name the following: (2012)
(a) A metal which is preserved in kerosene
(b) A lustrous coloured non metal
(c) A metal which can melt while kept on palm,
(d) A metal, which is a poor conductor of heat.
(c) Gallium and Caesium
(d) Lead and mercury
Define Amphoteric oxides? Give two examples of such oxides. (2012)
Some metal oxides show both acidic as well as basic behaviour. Those metal oxides which react with both acids as well as bases to produce salts and water are known as amphoteric oxides.
For example: Aluminium oxide, Zinc oxide
Give reason for the following: (2013)
(a) Sodium metal is kept immersed in kerosene.
(b) Blue colour of copper sulphate solution disappears when some aluminium powder is added in it.
(a) Sodium metal is so reactive that it reacts vigorously with the oxygen (of air). It catches fire and starts burning when kept open in the air. Sodium metal is stored under kerosene oil to prevent its reaction with oxygen, moisture and carbon dioxide of air.
(b) When aluminium powder is put in copper sulphate solution, then the blue colour of copper sulphate solution
Since Al is more reactive than Cu, it displaces Cu from CuSO4 solution and forms colourless Al2(SO4)3.
A thin zinc plate was kept in a glass container having CuSO2 solution. On examining it was found that the blue colour of the solution is getting lighter and lighter. After a few days when the zinc plate was taken out of the solution, a number of small holes were noticed in it. State the reason and write chemical equation of the reaction. (2014)
A strip of zinc metal is put in copper sulphate solution. The blue colour of copper sulphate solution fades gradually due to the formation of colourless zinc sulphate solution. Since zinc is more reactive than copper, zinc displaces copper from copper sulphate solution. Zinc metal is consumed and hence a number of small holes were formed in the zinc strip.
Reverse of the following chemical reaction is not possible:
Zn (s) + CuSO4 (aq) → ZnSO4 (aq) + Cu (s)
Justify this statement with reason.
ZnSO4 (aq) + Cu (s) → × (no reaction)
Because Cu is less reactive than Zn in the activity series. Therefore, less reactive metal (Cu) does not displace more reactive metal (Zn) from its salt solution. Thus, this reaction is not possible.
List four important properties of aluminium which are responsible for its great demand in industry. (2015)
Important properties of aluminium:
- It is a light metal.
- It does not corrode as it forms a protective layer of oxide which prevents it from further oxidation.
- It is a good conductor of heat and electricity.
- It is used as a reducing agent in the extraction of metals from the oxide.
A metal ‘M’ is found in nature as its carbonate. It is used in the galvanization of iron. Identify ‘M’ and name its ore. How will you convert this ore into free metal? (2015)
‘M’ = Zinc metal
Zinc occurs as Zinc Carbonate in calamine ore, ZnCO3.
Zinc can be extracted from the ore by:
(i) Zinc Carbonate is first converted into Zinc Oxide by calcination. When calamine ore (zinc carbonate) is heated strongly in the absence of air, it decomposes to form zinc oxide and carbon dioxide.
(ii) Zinc metal is then extracted from zinc oxide by reduction with carbon (coke).
Write down important properties of ionic compounds. (2017 D)
- Ionic compounds are generally hard and solids.
- Ionic compounds have high melting and boiling points.
- Ionic compounds are mostly soluble in water and insoluble in solvents like kerosene oil, alcohols, etc.
- In their molten state or aqueous solution these are good conductors of electric current.
State two ways for preventing rusting of iron articles. (2017 OD)
- By applying grease and paints on the iron particles.
- By coating of zinc layer over the iron articles by Galvanisation process.
Metals and Non-metals Class 10 Important Questions Short Answer Type II
A reddish brown coloured metal, used in electrical wires, when powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas is passed over this back substance, it regains its original colour. Based on the above information answer the following questions:
(i) Name the metal and the black coloured substance formed.
(ii) Write balanced chemical equations for both the reactions. (2012)
(i) The reddish brown coloured metal used in electric wires is Copper.
When copper is heated strongly in air, it combines with oxygen to form Copper (II) oxide, a black oxide.
(a) Why does calcium start floating when added to water? (2012)
(b) Most of the metals do not give hydrogen while reacting with nitric acid. Why?
(c) Write equation for the reaction of iron with steam. Name the compound of iron obtained.
(a) The reaction of calcium with water is less violent. The heat evolved is not sufficient for hydrogen to catch fire.
Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g)
Calcium starts floating because the bubbles of hydrogen gas formed stick to the surface of the metal.
(b) Most of the metals do not give hydrogen while reacting with nitric acid because HNO3 is a strong oxidising agent. It oxidises the H2 produced to water and itself gets reduced to any of the nitrogen oxides (N2O, NO, NO2).
(c) Iron reacts with steam to form iron oxide and hydrogen
Write balanced equation for the reaction of:
(i) Aluminium when heated in air. Write the name of the product.
(ii) Iron with steam. Name the product obtained.
(iii) Calcium with water. Why does calcium start floating in water? (2012)
(i) When aluminium is heated in air, it forms aluminium oxide.
(ii) When iron is reacted with steam, it forms iron oxide and hydrogen.
(iii) The reaction of calcium with water is less violent, and the heat evolved in this reaction is not sufficient for hydrogen to catch fire. So calcium starts floating in water because the bubbles of hydrogen gas formed stick to the surface of the metal.
Ca (s) + 2H2O (l) → Ca(OH)2 (aq) + H2 (g) + Heat
Define the term ‘metallurgy’, and fill appropriate terms in the blanks: (2013)
The four major steps involved in metallurgy are:
(i) ……of ore.
(ii) Conversion of ore into its ……..
(iii) Reduction of oxides of ores into …….
(iv) …….of metal.
The various processes involved in the extraction of metals from their ores and their refining are known as metallurgy.
The four major steps involved in metallurgy are:
(i) Concentration of ore.
(ii) Conversion of ore into its metal oxide
(iii) Reduction of oxides of ores into metal.
(iv) Refining of impure metal.
Draw a flow diagram to show extraction of metals of medium reactivity from their sulphide ore.
(b) Difference between Roasting and Calcination. (2013)
(a) Flow diagram to show extraction of metals of medium reactivity from their sulphide ores:
- It is done in case of sulphide ores.
- In this, the ore is heated in the presence of air to convert it into oxide compound.
- The gas given out is SO2 (sulphur dioxide) gas.
- It is done in case of carbonate ores.
- The carbonate ore is heated in the absence of air to convert it into oxide.
- The gas given out is CO2 (Carbon dioxide) gas.
State reason for the following:
(i) Lemon is used for restoring the shine of tarnished copper vessels.
(ii) A metal sulphide is converted into its oxide to extract the metal from the sulphide ore.
(iii) Copper wires are used in electrical connections.
(i) When a copper object remains in damp air for a considerable time, then copper reacts slowly with carbon dioxide and water in air to form a green coating of basic copper carbonate on its surface. If corroded copper vessels are treated with lemon which is acidic in nature, the acid solution dissolves green coloured basic copper carbonate and makes them look shiny.
(ii) It is easier to obtain metals from their oxides (by reduction) than from sulphides. So before reduction, the metal sulphide ore is converted into metal oxide.
(iii) Copper metal is the next best conductor of electricity after silver metal. So electric wires are made of copper (as silver being a costly metal can not be used for making electric wires).
Differentiate between the following with suitable examples: (2015)
(i) mineral and ore
(ii) corrosion and rancidity
(iii) malleability and ductility
(i) Difference between Mineral and Ore
- The natural materials in which the metals or their compounds are found in earth are called minerals.
- Some minerals may contain only a small percentage of the metal and some may contain a large percentage of metals.
- Those minerals from which the metals can be extracted conveniently and profitably are called ores.
- An ore contains a good percentage of the metal.
(ii) Difference between Corrosion and Rancidity
- The tarnishing of the metals by the attack of moisture, oxygen and other acidic oxides in the air is called corrosion.
- Example: Rusting of iron.
- When fats and oils present in the food get oxidized, the smell and taste of the food changes. This is called rancidity.
- Example: Potato-chips kept in N2 gas to check rancidity.
(iii) Difference between Malleability and Ductility
- The property which allows the metals to be hammered into thin sheets is called malleability.
- Gold and silver metals are the best malleable metals.
- The property which allows the metals to be drawn into thin wires is called ductility.
- Gold is the most ductile metal.
You are given samples of three metals sodium, magnesium and copper. Suggest any two activities to arrange them in order of their decreasing reactivity. (2015)
Given three metals – sodium (Na), magnesium (Mg), copper (Cu)
Activity I. When the three given metals Na, Mg and Cu are added to magnesium chloride solution separately taken in three different test tubes, we will find that displacement reactions will take place in the following manner:
This shows that Na is the most reactive metal as it displaces Mg from MgCl2 solution.
Activity II. When Na, Mg and Cu metals are taken in three different test tubes and CuSO4 solution is added in each test tube, we will find that displacement reactions will take place in the following manner:
This shows that Cu is the least reactive metal.
Order of decreasing reactivity: Na > Mg > Cu.
Differentiate between metals and non-metals on the basis of their chemical properties. (2017 OD)
Differentiate between Metals and Non-metals
- Metals form basic oxides with oxygen of air.
- Metals can displace hydrogen from dilute acids.
- Metals show displacement reactions on the basis of their reactivity series.
- Non-metals form acidic oxides with oxygen of air.
- Non-metals cannot displace hydrogen from dilute acids.
- Non-metals do not show such displacement reactions.
Metals and Non-metals Class 10 Important Questions Long Answer Type
(a) In the formation of compound between two atoms A and B, A loses two electrons and B gains one electron.
(i) What is the nature of bond between A and B?
(ii) Suggest the formula of the compound formed between A and B.
(b) On similar lines explain the formation of MgCl2 molecule.
(c) Common salt conducts electricity only in the molten state. Why?
(d) Why is melting point of NaCl high? (2012)
(i) Ionic bond is formed between A and B.
(b) (i) Mg has 2 electrons in its outermost shell so it loses its 2 electrons to achieve the inert gas configuration of eight valence electrons and forms positively charged ion or divalent cation.
(ii) Cl has 7 electrons in its outermost shell so it gains one electron to achieve the stable inert gas configuration and forms negatively charged ion or monovalent anion.
(c) Common salt (NaCl) is an ionic compound which conducts electricity only in molten state because in molten state the electrostatic forces of attraction between oppositely charged ions (Na+ and Cl–) are overcome due to heat. Thus the ions move freely and conduct electricity.
(d) NaCl is an ionic compound so there is a strong force of attraction between the positively charged sodium ion and negatively charged chloride ion. Therefore a considerable amount of energy is required to break the strong interionic attraction. Thus NaCl has high melting point.
(a) Show the formation of magnesium chloride and sodium chloride by transfer of electrons. (2012)
(b) Identify the ions present in these compounds.
(c) Why do ionic compounds not conduct electricity in the solid state?
(a) (i) Sodium (Na) and Magnesium (Mg) have 1 and 2 electrons respectively in the outermost shells of their atoms, so they lose their electrons to achieve the inert gas electron configuration of eight valence electrons and form positively charged ions or cations.
On the other hand, Cl has seven electrons in its atom so it gains one electron to acquire inert gas configuration and forms negatively charged ion or an anion.
(iii) Ionic compounds in the solid state do not conduct electricity because movement of ions in the solid state is not possible due to their rigid structure.
The metals extracted from their ores are not very pure. They contain impurities, which can be removed by the process of refining. Name the most widely used process of refining impure metals. Draw a diagram of the apparatus used for refining of copper metal and state:
(i) The name of the rods which are used as cathode and anode.
(ii) The electrolyte used during the process.
(iii) What happens to the pure metal when current passes through the electrolyte?
(iv) What happens to the soluble and insoluble impurities present in the impure copper? (2013)
The most common method for refining of impure metals is electrolytic refining.
Electrolytic Refining of Copper:
(i) A thin strip of pure metal is made the cathode whereas impure metal is made the anode.
(ii) Aqueous solution of salt of the metal to be refined.
(iii) On passing the current through the electrolyte, pure metal from the anode dissolves into the electrolyte. An equivalent amount of pure copper metal from the electrolyte gets deposited on the cathode. Pure copper metal is collected at the cathode.
(iv) The soluble impurities go into the solution while the insoluble impurities settle down at the bottom of the anode and are known as anode mud.
(a) Explain the steps for extraction of copper from its ore. Write the reaction involved. (2012)
(b) Draw a neat, labelled diagram for electrolytic refining of copper and explain the process.
Copper is found as Cu2S in nature. The concentrated Cu2S is roasted in presence of air and Cu2O is formed.
Copper oxide (Cu2O) is then heated in the absence of air. This reduces Cu2O into copper metal. The copper obtained is called blister copper because the SO2 produced during this reaction gets trapped inside its surface causing blisters to appear on the surface of copper metal.
(b) Electrolytic refining of copper:
Pure iron is soft and stretches easily when hot (2013)
(a) How does this property of iron change when:
(i) small amount of carbon is mixed with it?
(ii) nickel and chromium are mixed with it?
(b) Define an alloy. How is an alloy prepared?
(c) An alloy has low melting point and is therefore used for electrical fuse. Name the alloy and write its constituents.
(i) When small amount of carbon is mixed with iron, it becomes an alloy that is called steel. The carbon present in pig iron or cast iron makes it brittle and therefore, it cannot be used for structural purposes.
(ii) When iron is mixed with chromium and nickel, then stainless steel is obtained. Stainless steel does not rust at all.
Stainless steel is used for making cooking utensils, knives, scissors and surgical instruments etc.
(b) Alloy: An alloy is a homogeneous mixture of two or more metals or a metal and a non- metal. An alloy is generally prepared by heating the mixture of the metals (or metals and non-metals) to the molten state and then cooling the mixture to solidify at room temperature.
(c) A fuse wire is made up of an alloy of tin and copper or tin and lead (composition: 63% tin and 37% lead).
(a) Define corrosion. (2014)
(b) What is corrosion of iron called?
(c) How will you recognise the corrosion of silver?
(d) Why corrosion of iron is a serious problem?
(e) How can we prevent corrosion?
(a) Corrosion. Corrosion is the process in which metals are eaten up gradually by the action of air, moisture or a chemical on their surface.
(b) Rusting of iron metal is the most common form of corrosion.
(c) When silver objects are kept in air, they get tarnished and gradually turn black due to the formation of thin silver sulphide layer on their surface by the action of HjS of air.
(d) Corrosion weakens the iron and steel objects and structures such as railings, car bodies, bridges and ships, etc. and cuts short their life, therefore it is a serious problem.
(e) Methods to prevent corrosion:
- Galvanisation is a method used to protect steel and iron from rusting.
- Painting, greasing and oiling of metals is done to prevent corrosion.
- Cleaning metals regularly and carefully.
In Column I are given different methods of extraction. Name the methods used for the extraction of metals given in Column II: (2015)
|Column I||Column II|
|1. Reduction with carbon||Al, Zn, Na, Fe, Mn, Pb|
|2. Electrolytic reduction|
|3. Reduction with aluminium|
|Column I||Column II|
|1. Reduction with carbon||Zn, Fe, Pb|
|2. Electrolytic reduction||Al, Na|
|3. Reduction with aluminium||Mn|
(a) Explain any two physical properties of ionic compounds giving reason.
(b) List any two metals found in free state in earth’s crust. Where are they located in activity series?
(c) Metals towards the top of the activity series can not be obtained from their compounds by reducing with carbon. Why? (2015)
(a) Physical properties of ionic compounds:
(i) Ionic compounds are usually crystalline solids because their oppositely charged ions attract one another strongly and form a regular crystal structure.
(ii) Ionic compounds have high melting and high boiling points. The ionic compounds are made up of +ve and -ve ions. There is a strong force of attraction between the oppositely charged ions, so a lot of heat energy is required to break this force of attraction and melt or boil the ionic compounds.
(b) Gold and platinum metals are found in free state in the earth’s crust. These metals are located at the bottom in the activity series.
(c) Metals towards the top of the activity series are highly reactive. The oxides of highly reactive metals are very stable and can not be reduced by ‘carbon’ to obtain free metals because these metals have more affinity for oxygen than carbon.