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 8 of 18

1. Q141 CBSE 2026
   1. (i)Write the balanced chemical equations when : (I) A mixture of ${\text{Cu}}_2\text{O}$ ​and ${\text{Cu}}_2\text{S}$ is heated. (II) $\text{ZnS}$ is heated in ​the presence of oxygen.
   2. (ii)Give reasons for the following : (I) The wires carrying ​current in homes have a ​coating of PVC. (II) To make hot water tanks, copper is used and not ​steel.
   3. (iii)Show the formation of ​ionic compound $\text{CaO}$ with ​electron dot structure. [Atomic ​number : $\text{Ca}=20$, $\text{O}=8$]
   Show answer

   Self-reduction gives copper and roasting gives $\text{ZnO}$; PVC insulates, copper resists steam, and $\text{CaO}$ forms when Ca transfers two electrons to O.

   (i)(I) $2{\text{Cu}}_2\text{O}+{\text{Cu}}_2\text{S}\stackrel{\text{heat}}{\to }6\text{Cu}+{\text{SO}}_2$ (self-reduction). (II) $2\text{ZnS}+3{\text{O}}_2\stackrel{\text{heat}}{\to }2\text{ZnO}+2{\text{SO}}_2$ (roasting). (ii)(I) PVC is an electrical insulator; its coating on the copper wire keeps the current inside the wire and so prevents electric shocks and short circuits. (II) Copper does not react with water, hot water or steam, whereas the iron in steel reacts with steam, $3\text{Fe}+4{\text{H}}_2\text{O}⟶{\text{Fe}}_3{\text{O}}_4+4{\text{H}}_2$, and also rusts, so a steel tank would corrode; copper is also a good conductor of heat. (iii) Calcium ($2,8,8,2$) transfers its two valence electrons to oxygen ($2,6$), giving ${\text{Ca}}^{2+}$ ($2,8,8$) and ${\text{O}}^{2-}$ ($2,8$), which are held together by an ionic bond: $\text{Ca}{}_{\times }^{\times }+{}_{\cdot }^{\cdot }\stackrel{\cdot \cdot }{\underset{\cdot \cdot }{O}}⟶{\text{Ca}}^{2+}{\left[{}_{\times }^{\times }\stackrel{\cdot \cdot }{\underset{\cdot \cdot }{O}}{}_{\cdot }^{\cdot }\right]}^{2-}$

   Step-by-step solution →
2. Q142 CBSE 2026
   During extraction of metals, electrolytic refining ​is used to obtain pure ​metals.

   1. (i)Which material will be used as cathode and ​anode for refining ​of zinc metal by this process ?
   2. (ii)Name the ​electrolyte used in this process. Where do we get pure zinc after ​passing ​electric current ?
   3. (iii)How does zinc prevent rusting of iron ? Also, ​name the process.
   Show answer

   Impure zinc anode, pure zinc cathode and acidified zinc sulphate electrolyte give pure zinc at the cathode; a zinc coat protects iron by galvanisation.

   (i) Both electrodes are made of zinc: the anode is a thick block (plate) of impure zinc, connected to the positive terminal of the battery, and the cathode is a thin strip (sheet) of pure zinc, connected to the negative terminal. (ii) The electrolyte is a solution of zinc sulphate, ${\text{ZnSO}}_4$, acidified with a little dilute sulphuric acid — that is, a solution of a salt of the same metal. On passing the current, zinc from the impure anode dissolves into the solution and pure zinc is deposited at the cathode, so we get the pure zinc on the cathode. The insoluble impurities settle below the anode as anode mud. (iii) A layer of zinc is coated on the iron article. It protects the iron in two ways: it acts as a barrier that keeps air (oxygen) and moisture away from the iron surface, and because zinc is more reactive than iron it is oxidised in preference to iron, so even a scratched coating goes on protecting the iron beneath (sacrificial protection). The process is called galvanisation.

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3. Q143 CBSE 2025
   The ​products ​formed when ​Aluminium and Magnesium are ​burnt ​in the ​presence of air respectively are :

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

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

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4. Q144 CBSE 2025
   A metal, ​M, displaces iron ​from aqueous ​solution of ferrous sulphate but ​fails to do so in case ​of aqueous ​solution ​of aluminium sulphate. The metal M is

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

   (d) Zinc

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5. Q145 CBSE 2025
   The most common method of extraction of ​metals ​from ​their oxide ​ores is ​:

   1. (a)Reduction with carbon
   2. (b)Reduction with hydrogen
   3. (c)Reduction with aluminium
   4. (d)Electrolytic reduction
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   (a) Reduction with carbon

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6. Q146 CBSE 2025
   The most malleable metals are :

   1. (a)Iron and gold
   2. (b)Copper and silver
   3. (c)Silver and gold
   4. (d)Gold and copper
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   (c) Silver and gold

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7. Q147 CBSE 2025
   The property by ​virtue of ​which a solid ​material can be drawn ​into ​thin wires ​is called ​:

   1. (a)malleability
   2. (b)ductility
   3. (c)rigidity
   4. (d)resistivity
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   (b) ductility

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8. Q148 CBSE 2025
   Select from the following ​a metal which ​does not ​react with ​cold as ​well as hot ​water ​:

   1. (a)Calcium
   2. (b)Iron
   3. (c)Magnesium
   4. (d)Sodium
   Show answer

   (b) Iron

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9. Q149 CBSE 2025
   An element ‘M’ has ​25% of the electrons ​filled in ​the ​third ​shell ​as in the second shell. The element ‘M’ is ​:

   1. (a)Sodium
   2. (b)Magnesium
   3. (c)Aluminium
   4. (d)Calcium
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   (b) Magnesium

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10. Q150 CBSE 2025
    Which ​one ​of ​the ​following ​metals is protected from corrosion by a layer of its own oxide ​?

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

    (a) Aluminium

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11. Q151 CBSE 2025
    Consider ​the following cases ​:

    1. (i)${\text{CaSO}}_4+\text{Mg}$
    2. (ii)${\text{CuSO}}_4+\text{Ca}$
    3. (iii)${\text{ZnSO}}_4+\text{Fe}$
    4. (iv)${\text{FeSO}}_4+\text{Zn}$ The ​cases in which ​new products ​will form, ​are :

    1. (a)(i) and (ii)
    2. (b)(ii) and (iv)
    3. (c)(iii) and (iv)
    4. (d)(ii) and (iii)
    Show answer

    (b) (ii) and (iv)

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12. Q152 CBSE 2025
    Aluminium ​powder is ​used ​in thermit ​welding ​because :

    1. (a)Its reaction with iron is highly exothermic.
    2. (b)When it is heated with iron (III) oxide, molten iron is obtained.
    3. (c)When it is heated with iron (III) oxide, molten aluminium oxide is obtained to join railway tracks.
    4. (d)Its melting point is low as compared to iron and a molten alloy of iron and aluminium is formed on heating which is used to join railway tracks.
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    (b) When it is heated with iron (III) oxide, molten iron is obtained.

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13. Q153 CBSE 2025
    Which one of the following oxides reacts ​with HCl as ​well ​as ​NaOH to ​form corresponding salt and water ​?

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

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

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14. Q154 CBSE 2025
    Consider the reactions of ​dil. hydrochloric ​acid with the following metals ​: Aluminium, ​Copper, Iron, ​Magnesium and Zinc The ​correct ​observation is :

    1. (a)Most vigorous reaction with aluminium and no reaction with iron
    2. (b)Most vigorous reaction with magnesium and no reaction with iron
    3. (c)Most vigorous reaction with magnesium and no reaction with copper
    4. (d)Most vigorous reaction with zinc and no reaction with copper
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    (c) Most vigorous reaction with magnesium and no reaction with copper

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15. Q155 CBSE 2025
    A metal, 'X', on treatment with ​sodium hydroxide liberates a gas 'G'. It also ​liberates the ​same gas, 'G' ​on treatment with ​dilute sulphuric acid. Based ​on above information, 'X' and ​'G' ​respectively are

    1. (a)Copper and Sulphur dioxide
    2. (b)Zinc and Sulphur dioxide
    3. (c)Zinc and Hydrogen
    4. (d)Copper and Hydrogen
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    (c) Zinc and Hydrogen

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16. Q156 CBSE 2025
    Select ​ionic ​compounds from ​the ​following :

    1. (a)${\text{CCl}}_4$
    2. (b)$\text{KCl}$
    3. (c)$\text{HCl}$
    4. (d)$\text{NaCl}$

    1. (a)(b) and (c)
    2. (b)(c) and (d)
    3. (c)(a) and (c)
    4. (d)(b) and (d)
    Show answer

    (d) (b) and (d)

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17. Q157 CBSE 2025
    Study the following cases ​:

    1. (i)${\text{CuSO}}_4+\text{Mg}⟶$
    2. (ii)${\text{FeSO}}_4+\text{Pb}⟶$
    3. (iii)${\text{CaSO}}_4+\text{Al}⟶$
    4. (iv)${\text{ZnSO}}_4+\text{Ca}⟶$ The case/cases in which ​new ​product(s) will form is/are ​:

    1. (a)Only (i)
    2. (b)Only (iii)
    3. (c)(i) and (iv)
    4. (d)(i), (ii) and (iv)
    Show answer

    (c) (i) and (iv)

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18. Q158 CBSE 2025
    Reaction between two elements A ​and B, ​forms a compound C. A loses ​electrons and B gains electrons. Which ​one ​of the following ​properties will not be shown by compound C ?

    1. (a)It has high melting point.
    2. (b)It is highly soluble in water.
    3. (c)It has weak electrostatic forces of attraction between its oppositely charged ions.
    4. (d)It conducts electricity in its molten state or aqueous solution.
    Show answer

    (c) It has weak electrostatic forces of attraction between its oppositely charged ions.

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19. Q159 CBSE 2025
    Two metals zinc and tin are ​dissolved separately ​in definite proportions in ​molten ​copper ​(the primary metal) to obtain ​two different alloys respectively known as ​:

    1. (a)Bronze and Brass
    2. (b)Brass and Solder
    3. (c)Brass and Bronze
    4. (d)Solder and Bronze
    Show answer

    (c) Brass and Bronze

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20. Q160 CBSE 2025
    Consider ​the following cases/reactions ​:

    1. (i)${\text{CuSO}}_4+\text{Al}\to$
    2. (ii)${\text{CaSO}}_4+\text{Mg}\to$
    3. (iii)${\text{FeSO}}_4+\text{Pb}\to$
    4. (iv)${\text{ZnSO}}_4+\text{Ca}\to$ The cases/reactions ​in ​which new products ​will form are :

    1. (a)(i) and (iv)
    2. (b)(i) and (ii)
    3. (c)(ii) and (iii)
    4. (d)(i), (ii) and (iv)
    Show answer

    (a) (i) and (iv)

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