NCERT Exemplar Class 10 Science Chapter 3 Metals And Non Metals

Chapter 3 Metals And Non Metals NCERT Exemplar for class 10 Science

NCERT Exemplar Solutions for Class 10 Science Chapter 3 Metals and Non-metals are available here for free to download. These solutions will enable students to develop a clear understanding of important topics as well as different types of tricky questions. Students can also go through the answers provided at one place and once they get acquainted with the NCERT Exemplar, they will be able to study productively and perform well in the board exam. NCERT Chapter 3 is available here in PDF for easy access and download. The content provided over here is created with respect to upgraded CBSE syllabus(2024-25).

Students already know that, in Chemistry, elements are classified as metals and non-metals. In Chapter 3 of the Class 10 Science textbook, they will explore the topic in more detail. They will learn about the physical as well as the chemical properties of metals and non-metals and the main differences between various concepts and recognise and classify chemical reactions or changes.

1. Which of the following property is generally not shown by metals?

(a) Electrical conduction

(b) Sonorous in nature

(c) Dullness

(d) Ductility

Soln:

Answer is (c) Dullness

2. The ability of metals to be drawn into thin wires is known as

(a) ductility

(b) malleability

(c) sonorousity

(d) conductivity

Soln:

The answer is (a) ductility

Explanation:

• Ductility is the property of metals to be drawn into thin wire.
• Malleability is the property of metals to be drawn into a thin wire
• Sonorousity is the ability of a metal to be sonorous in nature, which means it is capable of making a deep, ringing sound.
• Conductivity is the ability to conduct electricity

3. Aluminium is used for making cooking utensils. Which of the following properties of aluminium are responsible for the same?

(i) Good thermal conductivity

(ii) Good electrical conductivity

(iii) Ductility

(iv) High melting point

(a) (i) and (ii)

(b) (i) and (iii)

(c) (ii) and (iii)

(d) (i) and (iv)

Soln:

The answer is (d) (i) and (iv)

Explanation:

Ductility and electric conductivity have no relation to cooking hence thermal conductivity, and high melting point are the right answers.

4. Which one of the following metals does not react with cold as well as hot water?

(a) Na

(b) Ca

(c) Mg

(d) Fe

Soln:

The answer is (d) Fe

Explanation:

Sodium and Calcium react vigorously with water and Magnesium reacts with hot water to form Magnesium Oxide. Iron does not react with cold and hot water, but it reacts with steam.

5. Which of the following oxide(s) of iron would be obtained on the prolonged reaction of iron with steam?

(a) FeO

(b) Fe2O3

(c) Fe3O4

(d) Fe2O3 and Fe3O4

Soln:

The answer is (c) Fe3O4

Explanation:

3Fe+4H2O →Fe3O4+4H2

6. What happens when calcium is treated with water?

(i) It does not react with water

(ii) It reacts violently with water

(iii) It reacts less violently with water

(iv) Bubbles of hydrogen gas formed stick to the surface of calcium

(a) (i) and (iv)

(b) (ii) and (iii)

(c) (i) and (ii)

(d) (iii) and (iv)

Soln:

The answer is (d) (iii) and (iv)

Explanation:

Calcium reacts vigorously with water and forms hydrogen, which will make calcium to float.

7. Generally, metals react with acids to give salt and hydrogen gas. Which of the following acids does not give hydrogen gas on reacting with metals (except Mn and Mg)?

(a) H2 SO4

(b) HCl

(c) HNO3

(d) All of these

Soln:

Answer is (c) HNO3

Explanation:

Nitric acid is a powerful oxidizing agent. It reacts with the metal to form water.

8. The composition of aqua-regia is

(a) Dil.HCl: Conc. HNO3 3: 1

(b) Conc.HCl: Dil. HNO3 3 : 1

(c) Conc.HCl: Conc.HNO3 3 : 1

(d) Dil.HCl: Dil.HNO3 3: 1

Soln:

The answer is (c) Conc.HCl: Conc.HNO3 3: 1

9. Which of the following are not ionic compounds?

(i) KCl

(ii) HCl

(iii) CCl4

(iv) NaCl

(a) (i) and (ii)

(b) (ii) and (iii)

(c) (iii) and (iv)

(d) (i) and (iii)

Soln:

The answer is (b) (ii) and (iii)

Explanation:

HCl and CCl4 are covalent compounds; hence they cannot be ionic.

10. Which one of the following properties is not generally exhibited by ionic compounds?

(a) Solubility in water

(b) Electrical conductivity in solid-state

(c) High melting and boiling points

(d) Electrical conductivity in a molten state

Soln:

The answer is (b) Electrical conductivity in solid-state

Explanation:

In an ionic compound, free ions are not available in a solid-state; hence solid ionic compounds cannot conduct electricity.

11. Which of the following metals exist in their native state in nature?

1. Cu
2. Au
3. Zn
4. Ag

(a) (i) and (ii)

(b) (ii) and (iii)

(c) (ii) and (iv)

(d) (iii) and (iv)

Soln:

The answer is (c) (ii) and (iv)

Explanation:

Gold and silver are non-reactive metals because of they are non-reactive they exist in their native state in nature.

12. Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining?

(i) Au

(ii) Cu

(iii) Na

(iv) K

(a) (i) and (ii)

(b) (i) and (iii)

(c) (ii) and (iii)

(d) (iii) and (iv)

Soln:

The answer is (d) (iii) and (iv)

Explanation:

Sodium and potassium are at the top in the reactivity series hence they can be refined by electrolytic refining.

13. Silver articles become black on prolonged exposure to air. This is due to the formation of

(a) Ag3N

(b) Ag2O

(c) Ag2 S

(d) Ag2S and Ag3N

Soln:

Answer is (c) Ag2S

Explanation:

Silver metal reacts with sulphur present in the atmosphere to form Ag2S. Ag2S is responsible for black colouration of silver articles.

14. Galvanisation is a method of protecting iron from rusting by coating it with a thin layer of

(a) Gallium

(b) Aluminium

(c) Zinc

(d) Silver

Soln:

The answer is(c) Zinc

Explanation:

Galvanization is a process of applying a layer of Zinc on iron by using electrolysis.

15. Stainless steel is a very useful material for our life. In stainless steel, iron is mixed with

(a) Ni and Cr

(b) Cu and Cr

(c) Ni and Cu

(d) Cu and Au

Soln:

The answer is (a) Ni and Cr

Explanation :

Stainless steel is an alloy of Iron, Nicker and chromium. This alloy makes the metal strong, durable and corrosion-resistant.

16. If copper is kept open in the air, it slowly loses its shining brown surface and gains a green coating. It is due to the formation of

(a) CuSO4

(b) CuCO3

(c) Cu(NO3 ) 2

(d) CuO

Soln:

The answer is (d) CuO

Explanation:

On exposure to air, copper reacts to atmospheric oxygen to form copper oxide layer which is green in colour.

17. Generally, metals are solid in nature. Which one of the following metals is found in liquid state at room temperature?

(a) Na

(b) Fe

(c) Cr

(d) Hg

Soln:

The answer is (d) Hg

18. Which of the following metals are obtained by electrolysis of their chlorides in molten state?

(i) Na

(ii) Ca

(iii) Fe

(iv) Cu

(a) (i) and (iv)

(b) (iii) and (iv)

(c) (i) and (iii)

(d) (i) and (ii)

Soln:

The answer is (d) (i) and (ii)

Explanation:

Sodium and Calcium are in the top, in reactivity series

19. Generally, non-metals are not lustrous. Which of the following nonmetal is lustrous?

(a) Sulphur

(b) Oxygen

(c) Nitrogen

(d) Iodine

Soln:

The answer is (d) Iodine

20. Which one of the following four metals would be displaced from the solution of its salts by the other three metals?

(a) Mg

(b) Ag

(c) Zn

(d) Cu

Soln:

The answer is (b) Ag

Explanation:

Because silver is a non-reactive metal, it can be displaced easily.

21. 2 mL each of concentrated HCl, HNO3 and a mixture of concentrated HCl and concentrated HNO3 in the ratio of 3: 1 were taken in test tubes labelled as A, B and C. A small piece of metal was put in each test tube. No change occurred in test tubes A and B, but the metal got dissolved in test tube C respectively. The metal could be

(a) Al

(b) Au

(c) Cu

(d) Pt

Soln:

The answer is (b) Au

Explanation:

Answer is gold because solution C is a mixture of Concentrated HCL and Concentrated HNO3 which is called aqua regia. Aqua Regia dissolves gold.

22. An alloy is

(a) an element

(b) a compound

(c) a homogeneous mixture

(d) a heterogeneous mixture

Soln:

The answer is (c) a homogeneous mixture

Explanation:

An Alloy is a homogeneous mixture because its composition is uniform.

23. An electrolytic cell consists of

(i) positively charged cathode

(ii) negatively charged anode

(iii) positively charged anode

(iv) negatively charged cathode

(a) (i) and (ii)

(b) (iii) and (iv)

(c) (i) and (iii)

(d) (ii) ad (iv)

Soln:

The answer is (b) (iii) and (iv)

24. During electrolytic refining of zinc, it gets

(a) deposited on cathode

(b) deposited on anode

(c) deposited on the cathode as well as anode

(d) remains in the solution

Soln:

The answer is (a) deposited on cathode

Explanation:

Zinc is positively charged hence it moves towards the negatively charged cathode.

25. An element, A, is soft and can be cut with a knife. This is very reactive to air and cannot be kept open in the air. It reacts vigorously with water. Identify the element from the following

(a) Mg

(b) Na

(c) P

(d) Ca

Soln:

The answer is (b) Na

Explanation:

Sodium is soft which can be cut with a knife. Sodium reacts with water and air vigorously hence it is kept in kerosene.

26. Alloys are homogeneous mixtures of a metal with a metal or nonmetal. Which among the following alloys contain non-metal as one of its constituents?

(a) Brass

(b) Bronze

(c) Amalgam

(d) Steel

Soln:

The answer is (d) Steel

Explanation:

Steel is an alloy made up of carbon and iron where carbon is a non-metal.

27. Which among the following statements is incorrect for magnesium metal?

(a) It burns in oxygen with a dazzling white flame

(b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas

(c) It reacts with hot water to form magnesium hydroxide and evolves hydrogen gas

(d) It reacts with steam to form magnesium hydroxide and evolves hydrogen gas

Soln:

The answer is (b) It reacts with cold water to form magnesium oxide and evolves hydrogen gas

Explanation:

Magnesium reacts with cold water to form magnesium oxide and evolves hydrogen gas is a wrong statement because Magnesium Hydroxide is formed, not Magnesium oxide.

28. Which among the following alloys contain mercury as one of its constituents?

(a) Stainless steel

(b) Alnico

(c) Solder

(d) Zinc amalgam

Soln:

The answer is (d) Zinc amalgam

Explanation:

Zinc amalgam is an alloy of Mercury and Zinc

29. Reaction between X and Y, forms compound Z. X loses electron and Y gains electron. Which of the following properties is not shown by Z?

(a) Has a high melting point

(b) Has a low melting point

(c) Conducts electricity in molten state

(d) Occurs as solid

Soln:

The answer is (b) Has a low melting point

Explanation:

Here Z is an ionic compound and Ionic compounds have melting point hence option b) is a wrong statement.

30. The electronic configurations of three elements X, Y and Z are X — 2, 8; Y — 2, 8, 7 and Z — 2, 8, 2. Which of the following is correct?

(a) X is a metal

(b) Y is a metal

(c) Z is a non-metal

(d) Y is a non-metal and Z is a metal

Soln:

The answer is (d) Y is a non-metal and Z is a metal

Explanation:

Element Y has 3 electrons in its outer, which is electronegative in nature. Z has 2 electrons in its outermost shell hence it is electropositive. Hence it is a metal.

31. Although metals form basic oxides, which of the following metals form an amphoteric oxide?

(a) Na

(b) Ca

(c) Al

(d) Cu

Soln:

The answer is (c) Al

Explanation:

Oxides of Aluminum are both acidic and basic in nature. Hence aluminium oxides are amphoteric in nature.

32. Generally, non-metals are not conductors of electricity. Which of the following is a good conductor of electricity?

(a) Diamond

(b) Graphite

(c) Sulphur

(d) Fullerene

Soln:

The answer is (b) Graphite

33. Electrical wires have a coating of an insulating material. The material, generally used is

(a) Sulphur

(b) Graphite

(c) PVC

(d) All can be used

Soln:

Answer is (c) PVC

Explanation:

Sulphur is brittle in nature; hence it can be used and Graphite is a good conductor of electricity hence it cannot be used as an insulator.

34. Which of the following non-metals is a liquid?

(a) Carbon

(b) Bromine

(c) Phosphorus

(d) Sulphur

Soln:

The answer is (b) Bromine

35. Which of the following can undergo a chemical reaction?

(a) MgSO4 + Fe

(b) ZnSO4 + Fe

(c) MgSO4 + Pb

(d) CuSO4 + Fe

Soln:

The answer is (d) CuSO4 + Fe

Explanation:

Iron is more reactive than copper hence it displaces copper in the reaction to form Feso4.

37. Iqbal treated a lustrous, divalent element M with sodium hydroxide. He observed the formation of bubbles in a reaction mixture. He made the same observations when this element was treated with hydrochloric acid. Suggest how can he identify the produced gas. Write chemical equations for both the reactions.

Soln:

To identify the produced gas, a lighted matchstick should be brought near the gas. If the matchstick burns with a “pop” sound, it indicates the evolution of Hydrogen gas.

M+ 2NaOH → Na2MO2+ H2

With HCl

M+ 2HCl →MCl2+H2

38. During the extraction of metals, electrolytic refining is used to obtain pure metals. (a) Which material will be used as anode and cathode for refining of silver metal by this process? (b) Suggest a suitable electrolyte also. (c) In this electrolytic cell, where do we get pure silver after passing electric current?

Soln:

1. During extraction of metals, impure metal will be used as an anode, and pure metal is used as a cathode for refining of silver metal by this electrolytic refining.
2. Silver Sulphate or Silver Nitrate
3. Pure silver is obtained on the cathode

39. Why should the metal sulphides and carbonates be converted to metal oxides in the process of extraction of metal from them?

Soln:

Metal sulphides and carbonates are converted to metal oxides in the process of extraction of metal from them because metals can be obtained easier in oxide form than its sulphide or carbonate form.

40. Generally, when metals are treated with mineral acids, hydrogen gas is liberated, but when metals (except Mn and Mg), treated with HNO3, hydrogen is not liberated, why?

Soln:

HNO3 is a strong oxidizing agent. It oxidises the liberated Hydrogen into the water while converting itself to nitrogen oxide.

41. Compound X and aluminium are used to join railway tracks. (a) Identify the compound X (b) Name the reaction (c) Write down its reaction.

Soln:

1. Answer is Fe2O3
2. The involved reaction is a thermite reaction which is also called as aluminothermy
3. Fe2O3(s) + 2Al(s)→ Al2O3 (s) + 2Fe(s) + Heat Ferric oxide Aluminium Aluminium Iron Oxide.

42. When a metal X is treated with cold water, it gives a basic salt Y with molecular formula XOH (Molecular mass = 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z and also write the reaction involved.

Soln:

X is Na because the molecular mass of NaOH is 40.

Hence Y is NaOH

Z is hydrogen has which catches fire when reacts with water.

2Na+2H2O → 2NaOH+H2

43. A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y and Z.

Soln:

X is Carbon, Y and Z are Diamond and Graphite, which are allotropes of the carbon.

44. The following reaction takes place when the aluminium powder is heated with MnO2

3 MnO2 (s) + 4 Al (s) → 3 Mn (l) + 2 Al2O3 (l) + Heat

(a) Is aluminium getting reduced? (b) Is MnO2 getting oxidised?

Soln:

In this reaction, aluminium gets oxidized as oxygen gets combined with it. Since oxygen is removed from MnO2, it is getting reduced.

45. What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires?

Soln:

Solder alloy is made of Lead and aluminium. Its low melting point makes it suitable for welding electrical wires.

46. A metal A, which is used in thermite process, when heated with oxygen gives an oxide B, which is amphoteric in nature. Identify A and B. Write down the reactions of oxide B with HCl and NaOH.

Soln:

Metal A is Aluminium and B is Al→2O3

With HCl

Al2O3+ 6HCl →2AlCl3+3H2O

With NaOH

Al2O3+2NaOH →2NaAlO2+H2O

47. A metal that exists as a liquid at room temperature is obtained by heating its sulphide in the presence of air. Identify the metal and its ore and give the reaction involved.

Soln:

Mercury is the metal which is liquid at room temperature. The Ore of Mercury is Cinnabar. When we heat cinnabar in atmospheric oxygen, the following reaction takes place.

2HgS + 3O2→ 2HgO + 2SO2

Mercuric oxide is again heated to get Mercury and Oxygen

2HgO

→heat

Hg+O2

48. Give the formulae of the stable binary compounds that would be formed by the combination of the following pairs of elements.

(a) Mg and N2

(b) Li and O2

(c) Al and Cl2

(d) K and O2

Soln:

1. Magnesium Nitride (Mg3N2)
2. Lithium Oxide( Li2O)
3. Aluminium Chloride( AlCl3)
4. Potassium Oxide ( K2O)

49. What happens when

(a) ZnCO3 is heated in the absence of oxygen?

(b) a mixture of Cu2O and Cu2S is heated?

Soln:

a) When ZnCO3 is heated in the absence of oxygen Zinc Oxide and Carbon-di-oxide are liberated.

ZnCo3 →ZnO + CO2

b) When a mixture of Cu2O and Cu2S is heated, we get pure copper

2 Cu2O+ Cu2S →6Cu+SO2

50. A non-metal A is an important constituent of our food and forms two oxides B and C. Oxide B is toxic whereas C causes global warming

(a) Identify A, B and C

(b) To which Group of Periodic Table does A belong?

Soln:

a) A is Carbon. B is Carbon monoxide and C is Carbon-dioxide

b) Group 14

51. Give two examples each: The metals that are good conductors and poor conductors of heat, respectively.

Soln:

Good conductors- Iron and Copper

Bad conductors- Lead and Mercury

52. Name one metal and one non-metal that exist in a liquid state at room temperature. Also, name two metals having a melting point less than 310 K (37°C)

Soln:

Mercury and Bromine are liquid at room temperature. Caesium and Gallium are the metals whose melting point is less than 310K(37°c).

53. An element A reacts with water to form a compound B which is used in whitewashing. The compound B on heating forms an oxide C which on treatment with water gives back B. Identify A, B and C and give the reactions involved.

Soln:

A is calcium, B is calcium Hydroxide, and C is Calcium Oxide.

Ca+2H2O →Ca(OH)2+ H2

Ca(OH)2 →CaO+H2O

CaO+H2O→ Ca(OH)2

54. An alkali metal A gives a compound B (molecular mass = 40) on reacting with water. The compound B gives a soluble compound C on treatment with aluminium oxide. Identify A, B and C and give the reaction involved.

Soln:

A is sodium and B is Sodium Hydroxide. Because the molecular mass of NaOH is 40. So C is Sodium Aluminate.

Al2O3 +2NaOH →2NaAlO2+H2O

55. Give the reaction involved during the extraction of zinc from its ore by (a) roasting of zinc ore (b) calcination of zinc ore

Soln:

1. 2ZnS + 3O2→2ZnO + 2SO2.
2. ZnCo3→ZnO+CO

56. A metal M does not liberate hydrogen from acids but reacts with oxygen to give a black colour product. Identify M and black coloured product and also explain the reaction of M with oxygen.

Soln:

Copper is the metal which does not react with acids. With oxygen, it forms Copper Oxide.

Metal M is Copper and black coloured product is copper oxide.

2Cu+ O2 →2CuO

57. An element forms an oxide A2O3 which is acidic in nature. Identify A as metal or non-metal.

Soln:

A is a non-metal because oxides of non-metals are acidic in nature.

58. A solution of CuSO4 was kept in an iron pot. After a few days, the iron pot was found to have a number of holes in it. Explain the reason in terms of reactivity. Write the equation of the reaction involved.

Soln:

Iron is more reactive than copper hence Iron displaces Copper to produce FeSO4. In this process, a portion of Iron Gets dissolved which results in Holes in the pot.

Fe+ CuSO4 →FeSO4+ Cu