Class 10 Science · Chapter 3

Metals and Non-metals

344 Class 10 Science questions on Metals and Non-metals from the NCERT textbook, NCERT Exemplar and CBSE board papers 2017–2026, each with its answer and a step-by-step solution.

CBSE Class 10 Science previous year papers, with answers →

Questions · page 13 of 18

1. Q241 CBSE 2023
   $2$ g of yellow sulphur powder is burnt ​in ​a china dish ​and the ​fumes are collected in a test tube. ​Water is added in the test tube and the solution is tested separately with blue ​and red litmus paper. The correct option is :

   1. (a)Blue litmus remains blue and red litmus turns blue.
   2. (b)Blue litmus turns red and red litmus remains red.
   3. (c)Blue litmus turns red and red litmus turns blue.
   4. (d)Blue litmus remains blue and red litmus remains red.
   Show answer

   (b) Blue litmus turns red and red litmus remains red.

   Step-by-step solution →
2. Q242 CBSE 2023
   A ​metal 'X' is used ​in thermite ​process. ​When X is burnt in air it ​gives an amphoteric ​oxide 'Y'. 'X' ​and 'Y' are respectively ​:

   1. (a)Fe and ${\text{Fe}}_2{\text{O}}_3$
   2. (b)Al and ${\text{Al}}_2{\text{O}}_3$
   3. (c)Fe and ${\text{Fe}}_3{\text{O}}_4$
   4. (d)Al and ${\text{Al}}_3{\text{O}}_4$
   Show answer

   (b) Al and ${\text{Al}}_2{\text{O}}_3$

   Step-by-step solution →
3. Q243 CBSE 2023
   Among the ​following, ​the metal ​with lowest density ​is :

   1. (a)Lithium
   2. (b)Lead
   3. (c)Magnesium
   4. (d)Aluminium
   Show answer

   (a) Lithium

   Step-by-step solution →
4. Q244 CBSE 2023
   Which of ​the ​following statements ​is true ​for an ​amphoteric ​oxide ?

   1. (a)It reacts only with acid and does not form water.
   2. (b)It reacts with acid as well as base to form salt and hydrogen gas.
   3. (c)It reacts with both acid as well as base to form salt and water.
   4. (d)It reacts only with base and does not form water.
   Show answer

   (c) It reacts with both acid as well as base to form salt and water.

   Step-by-step solution →
5. Q245 CBSE 2023
   Which one ​of the ​following ​metals is malleable ​and ​a poor conductor of electricity ?

   1. (a)Copper
   2. (b)Zinc
   3. (c)Lead
   4. (d)Silver
   Show answer

   (c) Lead

   Step-by-step solution →
6. Q246 CBSE 2023
   The ​metal which ​melts ​when ​kept ​on ​the palm is :

   1. (a)Sodium
   2. (b)Potassium
   3. (c)Lithium
   4. (d)Gallium
   Show answer

   (d) Gallium

   Step-by-step solution →
7. Q247 CBSE 2023
   The number of ​electrons ​in the ​outermost shell of ​the atom of ​a non-metal ​can be ​:

   1. (a)$1,2$ or $3$
   2. (b)$3,4$ or $5$
   3. (c)$5,6$ or $7$
   4. (d)$5,6$ or $8$
   Show answer

   (c) $5,6$ or $7$

   Step-by-step solution →
8. Q248 CBSE 2023
   In the process of ​galvanisation of ​iron, the metal ​used for ​the ​coating ​over iron ​is :

   1. (a)Aluminium
   2. (b)Gallium
   3. (c)Zinc
   4. (d)Lead
   Show answer

   (c) Zinc

   Step-by-step solution →
9. Q249 CBSE 2023
   The following diagram ​shows the electrolytic refining ​of ​copper : Which of the ​following ​statements is ​incorrect description of the ​process ?

   1. (a)The impure metal from the anode dissolves into the electrolyte.
   2. (b)The pure metal from the electrolyte is deposited on the cathode.
   3. (c)Insoluble impurities settle down at the bottom of the anode.
   4. (d)On passing the current through the electrolyte, the pure metal from the anode dissolves into the electrolyte.
   Show answer

   (a) The impure metal from the anode dissolves into the electrolyte.

   Step-by-step solution →
10. Q250 CBSE 2023
    Bronze is an alloy of

    1. (a)Copper and Zinc
    2. (b)Aluminium and Tin
    3. (c)Copper, Tin and Zinc
    4. (d)Copper and Tin
    Show answer

    (d) Copper and Tin

    Step-by-step solution →
11. Q251 CBSE 2023
    Which of ​the ​following metals ​do not ​corrode ​in moist air ​?

    1. (a)Copper
    2. (b)Iron
    3. (c)Gold
    4. (d)Silver
    Show answer

    (c) Gold

    Step-by-step solution →
12. Q252 CBSE 2023
    These consist of two ​statements ​– ​Assertion ​(A) ​and Reason (R). Answer this question selecting ​the appropriate option given below :

    Assertion (A): The colour of aqueous solution of copper sulphate turns colourless when a piece of lead is added to it.

    Reason (R): Lead is more reactive than copper, and hence displaces copper from its salt solution.

    1. (a)Both (A) and (R) are true and (R) is the correct explanation of (A).
    2. (b)Both (A) and (R) are true, but (R) is not the correct explanation of (A).
    3. (c)(A) is true, but (R) is false.
    4. (d)(A) is false, but (R) is true.
    Show answer

    (a) Both (A) and (R) are true and (R) is the correct explanation of (A).

    Step-by-step solution →
13. Q253 CBSE 2023
    Two statements are ​given ​— one labelled as Assertion (A) and the other labelled ​as ​Reason (R). Select the ​correct answer to ​this question from the codes (a), (b), (c) and (d) as given ​below.

    Assertion (A): Sodium oxide is an amphoteric oxide.

    Reason (R): Metal oxides which react with both acids as well as bases are known as amphoteric oxides.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (d) Assertion (A) is false, but Reason (R) is true.

    Step-by-step solution →
14. Q254 CBSE 2023
    Two statements are given ​— one labelled ​as Assertion (A) ​and the other ​labelled ​as Reason (R). Select the correct answer to this question from the codes (a), (b), (c) and (d) ​as given below.

    Assertion (A): It is possible to store copper sulphate solution in a container made of iron sheet.

    Reason (R): Iron is a more reactive metal than copper.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (d) Assertion (A) is false, but Reason (R) is true.

    Step-by-step solution →
15. Q255 CBSE 2023
    Two statements are given — one labelled as ​Assertion (A) and the other labelled as Reason (R). Select the correct answer to ​this question ​from the codes (a), ​(b), (c) and ​(d) ​as given below.

    Assertion (A): Sodium, calcium and magnesium are obtained by the electrolysis of their molten oxides.

    Reason (R): These metals have more affinity for oxygen than carbon.

    1. (a)Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
    2. (b)Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
    3. (c)Assertion (A) is true, but Reason (R) is false.
    4. (d)Assertion (A) is false, but Reason (R) is true.
    Show answer

    (d) Assertion (A) is false, but Reason (R) is true.

    Step-by-step solution →
16. Q256 CBSE 2023
    A metal ​'A' reacts violently with ​cold water ​and the gas evolved catches fire. Another metal 'B' when dipped in ​water starts floating. The metal 'C' ​does not react either with cold ​or hot ​water, but reacts with steam. The metal 'D' ​does not react with water at all. Identify the metals 'A', 'B', 'C' and 'D'.
    Show answer

    A is potassium, B is calcium, C is aluminium and D is copper.

    A is potassium (sodium is equally acceptable), B is calcium, C is aluminium (zinc or iron is equally acceptable) and D is copper (lead, silver or gold is equally acceptable).

    Step-by-step solution →
17. Q257 CBSE 2023
    When two compounds namely sodium chloride and calcium chloride ​are heated directly, one by ​one on the flame of ​a burner, they impart different colours to ​the flame. (i) Name ​the colour imparted ​by

    1. (1)sodium chloride and
    2. (2)calcium chloride. (ii) Are these compounds soluble in organic ​solvents such as kerosene or petrol ​? Justify your answer.
    Show answer

    Sodium chloride gives a golden-yellow flame and calcium chloride a brick-red flame; neither dissolves in kerosene or petrol.

    (i) Sodium chloride imparts a golden-yellow flame and calcium chloride imparts a brick-red flame, because the colour comes from the metal ion (${\text{Na}}^{+}$ and ${\text{Ca}}^{2+}$) and not from the chloride ion common to both. (ii) No. Both are ionic compounds whose ions are held in a lattice by strong electrostatic forces; kerosene and petrol are non-polar organic solvents whose molecules cannot solvate ions, so they cannot pull the lattice apart. These salts dissolve in water, a polar solvent, but not in kerosene or petrol.

    Step-by-step solution →
18. Q258 CBSE 2023
    Write ​the constituents of solder alloy. ​Which ​property of solder makes it suitable ​for welding electrical ​wires ?
    Show answer

    Solder is an alloy of lead and tin; its low melting point makes it suitable for welding electrical wires.

    Solder is an alloy of lead (Pb) and tin (Sn). It has a low melting point, so it melts easily and can be melted onto a joint to weld electrical wires together without melting the wires.

    Step-by-step solution →
19. Q259 CBSE 2023
    With the help of suitable chemical equations, list the two main differences between roasting ​and ​calcination. How ​is ​metal reduced from the product obtained after roasting/calcination of the ore ? ​Write ​the chemical equation for ​the reaction involved.
    Show answer

    Roasting is for sulphide ores in excess air, calcination for carbonate ores in limited air; carbon then reduces the oxide.

    Differences. (1) Roasting is carried out on a **sulphide** ore, calcination on a **carbonate** ore. (2) Roasting is done by heating strongly in the presence of **excess air**, calcination by heating strongly in the **absence** or a limited supply of air; roasting drives the sulphur off as ${\text{SO}}_2$, while calcination drives off ${\text{CO}}_2$. Roasting: $2\text{ZnS}+3{\text{O}}_2\stackrel{\text{heat}}{\to }2\text{ZnO}+2{\text{SO}}_2$. Calcination: ${\text{ZnCO}}_3\stackrel{\text{heat}}{\to }\text{ZnO}+{\text{CO}}_2$. Both give the metal **oxide**. The oxide is then reduced to the metal by heating it with a suitable reducing agent, usually carbon (coke): $\text{ZnO}+\text{C}\stackrel{\text{heat}}{\to }\text{Zn}+\text{CO}$.

    Step-by-step solution →
20. Q260 CBSE 2023
    1. (a)Copper reacts with a moist gas ‘A’ in the air and slowly loses ​its shiny brown surface. It turns green. Identify ‘A’ and the ​substance of the green coating formed on ​the surface of copper.
    2. (b)How is copper obtained ​from its ​sulphide ore ? Write the chemical equations for the reaction ​involved in its ​extraction.
    Show answer

    A is carbon dioxide and the green coating is basic copper carbonate; copper is obtained by heating its sulphide ore in air.

    (a) 'A' is carbon dioxide: in moist air, copper slowly reacts with carbon dioxide (together with the oxygen and water vapour of the air), loses its shiny brown surface and gains a green coat. The green substance is basic copper carbonate, ${\text{CuCO}}_3\cdot {\text{Cu(OH)}}_2$: $2\text{Cu}+{\text{H}}_2\text{O}+{\text{CO}}_2+{\text{O}}_2\to {\text{CuCO}}_3\cdot {\text{Cu(OH)}}_2$. (b) Copper is low in the activity series, so it is obtained from its sulphide ore, copper glance (${\text{Cu}}_2\text{S}$), by heating alone. The ore is heated strongly in air, which converts part of it into copper(I) oxide: $2{\text{Cu}}_2\text{S}+3{\text{O}}_2\stackrel{\text{heat}}{\to }2{\text{Cu}}_2\text{O}+2{\text{SO}}_2$. On further heating, the copper(I) oxide reacts with the remaining copper(I) sulphide to give copper: $2{\text{Cu}}_2\text{O}+{\text{Cu}}_2\text{S}\stackrel{\text{heat}}{\to }6\text{Cu}+{\text{SO}}_2$. The copper is then purified by electrolytic refining.

    Step-by-step solution →