Class 10 Science · Chapter 3

Metals and Non-metals

225 Class 10 Science questions on Metals and Non-metals from the NCERT textbook, NCERT Exemplar and CBSE board papers 2024–2026, each with its answer and a step-by-step solution.

CBSE Class 10 Science previous year papers, with answers →

Questions · page 2 of 12

1. Q21 NCERT · Intext Questions (Page 46)
   Samples ​of four metals A, B, ​C and ​D were taken and added to the following solution one by one. The results obtained have been tabulated as follows. Use the ​Table above to answer the following questions about metals A, B, C and D.

   1. (i)Which is ​the most reactive metal?
   2. (ii)What would you observe if B is added to a solution of Copper(II) sulphate?
   3. (iii)Arrange the metals A, B, C and D in ​the order of decreasing ​reactivity.

   Results of adding metals A, B, C and D to four salt solutions

   Metal	Iron(II) sulphate	Copper(II) sulphate	Zinc sulphate	Silver nitrate
   A	No reaction	Displacement
   B	Displacement		No reaction
   C	No reaction	No reaction	No reaction	Displacement
   D	No reaction	No reaction	No reaction	No reaction

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   B is the most reactive; B displaces copper, so the blue colour fades and reddish-brown copper deposits on B; the order is $\text{B}>\text{A}>\text{C}>\text{D}$.

   (i) B is the most reactive metal; it is the only one that displaces iron from iron(II) sulphate. (ii) B lies above copper in the reactivity series, so when B is added to copper(II) sulphate solution a displacement reaction occurs: the blue colour of the solution fades, a reddish-brown deposit of copper forms on the surface of B, and B slowly dissolves ($\text{B}+{\text{CuSO}}_4\text{(aq)}\to {\text{BSO}}_4\text{(aq)}+\text{Cu(s)}$, taking B as divalent). (iii) Order of decreasing reactivity: B > A > C > D.

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2. Q22 NCERT · Intext Questions (Page 46)
   Which ​gas is produced ​when ​dilute hydrochloric acid is added ​to a reactive metal? Write ​the ​chemical ​reaction when iron reacts with ​dilute ${\text{H}}_2{\text{SO}}_4$.
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   Hydrogen gas is produced; iron with dilute sulphuric acid gives iron(II) sulphate and hydrogen.

   Hydrogen gas (${\text{H}}_2$) is produced when dilute hydrochloric acid is added to a reactive metal (a metal above hydrogen in the reactivity series). Iron with dilute sulphuric acid: $\text{Fe(s)}+{\text{H}}_2{\text{SO}}_4\text{(aq)}\to {\text{FeSO}}_4\text{(aq)}+{\text{H}}_2\text{(g)}$; iron(II) sulphate and hydrogen are formed.

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3. Q23 NCERT · Intext Questions (Page 46)
   What ​would you ​observe when ​zinc is added to ​a solution of ​iron(II) sulphate? Write the chemical reaction that ​takes ​place.
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   Zinc displaces iron: the pale-green solution turns colourless and iron is deposited, $\text{Zn}+{\text{FeSO}}_4\to {\text{ZnSO}}_4+\text{Fe}$.

   Zinc is more reactive than iron, so it displaces iron from iron(II) sulphate solution. Observations: the pale-green colour of the iron(II) sulphate solution slowly fades and the solution becomes colourless (zinc sulphate), a greyish-black deposit of iron forms on the surface of the zinc, and the zinc slowly dissolves. Reaction: $\text{Zn(s)}+{\text{FeSO}}_4\text{(aq)}\to {\text{ZnSO}}_4\text{(aq)}+\text{Fe(s)}$ (a displacement reaction).

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4. Q24 NCERT · Intext Questions (Page 49)
   1. (i)Write the ​electron-dot structures for ​sodium, oxygen and magnesium.
   2. (ii)Show the formation ​of ${\text{Na}}_2\text{O}$ and $\text{MgO}$ by ​the transfer of electrons.
   3. (iii)What ​are the ions present in ​these compounds?
   Show answer

   Sodium and magnesium give electrons to oxygen, forming ${\text{Na}}_2\text{O}$ with ${\text{Na}}^{+}$ and ${\text{O}}^{2-}$, and $\text{MgO}$ with ${\text{Mg}}^{2+}$ and ${\text{O}}^{2-}$.

   (i) Electron-dot structures: Na with one dot (2,8,1), O with six dots (2,6), Mg with two dots (2,8,2), as in the figure. (ii) ${\text{Na}}_2\text{O}$: two sodium atoms each lose one electron and one oxygen atom gains both, $2\text{Na}\to 2{\text{Na}}^{+}+2e^{-}$ and $\text{O}+2e^{-}\to {\text{O}}^{2-}$, giving $({\text{Na}}^{+}{)}_2{\text{O}}^{2-}$, that is ${\text{Na}}_2\text{O}$. $\text{MgO}$: one magnesium atom loses two electrons and one oxygen atom gains them, $\text{Mg}\to {\text{Mg}}^{2+}+2e^{-}$ and $\text{O}+2e^{-}\to {\text{O}}^{2-}$, giving ${\text{Mg}}^{2+}{\text{O}}^{2-}$, that is $\text{MgO}$. (iii) ${\text{Na}}_2\text{O}$ contains ${\text{Na}}^{+}$ and ${\text{O}}^{2-}$ ions (two ${\text{Na}}^{+}$ for each ${\text{O}}^{2-}$); $\text{MgO}$ contains ${\text{Mg}}^{2+}$ and ${\text{O}}^{2-}$ ions (one of each).

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5. Q25 NCERT · Intext Questions (Page 49)
   Why ​do ​ionic compounds ​have high ​melting ​points?
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   Strong electrostatic attraction between the ions needs a large amount of heat energy to overcome, so ionic compounds melt at high temperatures.

   Ionic compounds are made of positively and negatively charged ions held together by strong electrostatic forces of attraction in a rigid structure. To melt such a solid these strong inter-ionic attractions must be overcome so that the ions can move freely, and this requires a considerable amount of heat energy. Hence ionic compounds have high melting points (for example, NaCl melts at 1074 K and CaO at 2850 K).

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6. Q26 NCERT · Intext Questions (Page 53)
   Define ​the following ​terms.

   1. (i)​Mineral
   2. (ii)Ore
   3. (iii)Gangue
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   Minerals occur naturally in the earth's crust; an ore is a mineral that yields metal profitably; gangue is the impurity in an ore.

   (i) Mineral: the elements or compounds which occur naturally in the earth's crust are called minerals. (ii) Ore: a mineral that contains a very high percentage of a particular metal, from which the metal can be extracted profitably, is called an ore (for example, cinnabar, HgS, is an ore of mercury). (iii) Gangue: the impurities such as soil, sand and rocky material with which an ore is contaminated when it is mined from the earth are called gangue; they are removed from the ore before the metal is extracted.

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7. Q27 NCERT · Intext Questions (Page 53)
   Name two metals ​which ​are ​found ​in ​nature in the ​free state.
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   Gold and silver are found free in nature because they are unreactive.

   Gold (Au) and silver (Ag) are found in nature in the free state. (Platinum and copper are also found free; copper and silver additionally occur in the combined state as sulphide or oxide ores.)

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8. Q28 NCERT · Intext Questions (Page 53)
   What chemical ​process is ​used ​for ​obtaining a metal from its ​oxide?
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   Reduction: the metal oxide is reduced, e.g. by carbon, to give the metal.

   Reduction. A metal is obtained from its oxide by reducing the oxide (removing its oxygen) with a suitable reducing agent: carbon for metals in the middle of the activity series, e.g. $\text{ZnO(s)}+\text{C(s)}\to \text{Zn(s)}+\text{CO(g)}$; a more reactive metal such as aluminium (thermit reaction), e.g. ${\text{Fe}}_2{\text{O}}_3\text{(s)}+2\text{Al(s)}\to 2\text{Fe(l)}+{\text{Al}}_2{\text{O}}_3\text{(s)}+\text{heat}$; heating alone for the least reactive metals, e.g. $2\text{HgO(s)}\stackrel{\text{heat}}{\to }2\text{Hg(l)}+{\text{O}}_2\text{(g)}$; and electrolytic reduction for the most reactive metals (Na, Mg, Ca, Al).

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9. Q29 NCERT · Intext Questions (Page 55)
   Metallic oxides of ​zinc, magnesium ​and ​copper were ​heated with ​the following ​metals. In which cases will you find ​displacement reactions taking place?

   Metal oxides heated with metals (cells to be filled in)

   Metal	Zinc	Magnesium	Copper
   Zinc oxide
   Magnesium oxide
   Copper oxide

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   Displacement occurs in three cases: zinc oxide with magnesium, copper oxide with zinc, and copper oxide with magnesium.

   Displacement reactions take place in three cases, where the metal is more reactive than the metal in the oxide (reactivity order Mg > Zn > Cu): (1) zinc oxide heated with magnesium, $\text{ZnO}+\text{Mg}\to \text{MgO}+\text{Zn}$; (2) copper oxide heated with zinc, $\text{CuO}+\text{Zn}\to \text{ZnO}+\text{Cu}$; (3) copper oxide heated with magnesium, $\text{CuO}+\text{Mg}\to \text{MgO}+\text{Cu}$. In the other six cases (ZnO with Zn or Cu; MgO with Zn, Mg or Cu; CuO with Cu) there is no displacement, because the metal is either the same as, or less reactive than, the metal in the oxide.

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10. Q30 NCERT · Intext Questions (Page 55)
    Which ​metals ​do not ​corrode ​easily?
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    Gold and platinum, and largely silver, do not corrode easily because they are very unreactive.

    Metals at the bottom of the reactivity series, the noble metals gold and platinum (and, to a large extent, silver), do not corrode easily, because they do not react with the oxygen, moisture, carbon dioxide and acids in their surroundings. Gold and silver do not react with oxygen even at high temperatures, which is why these metals are used for jewellery. (Silver does tarnish slowly, forming black silver sulphide with sulphur compounds in the air.)

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11. Q31 NCERT · Intext Questions (Page 55)
    What are alloys?
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    An alloy is a homogeneous mixture of two or more metals, or of a metal and a non-metal, such as brass.

    An alloy is a homogeneous mixture of two or more metals, or of a metal and a non-metal. It is prepared by first melting the primary metal, then dissolving the other elements in it in definite proportions, and cooling the mixture to room temperature. Alloying is done to improve the properties of a metal; for example, iron mixed with about 0.05 per cent carbon becomes hard and strong steel, and iron with nickel and chromium gives stainless steel, which does not rust. Examples: brass (Cu and Zn), bronze (Cu and Sn), solder (Pb and Sn), stainless steel (Fe, Ni and Cr); an alloy containing mercury is called an amalgam. Alloys have lower electrical conductivity and lower melting points than the pure metals.

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12. Q32 Exemplar · Multiple Choice Questions
    Which ​of the ​following property is ​generally ​not shown ​by ​metals?

    1. (a)Electrical conduction
    2. (b)Sonorous in nature
    3. (c)Dullness
    4. (d)Ductility
    Show answer

    (c) Dullness

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13. Q33 Exemplar · Multiple Choice Questions
    The ​ability ​of metals ​to be ​drawn into ​thin wire is ​known ​as

    1. (a)ductility
    2. (b)malleability
    3. (c)sonorousity
    4. (d)conductivity
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    (a) ductility

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14. Q34 Exemplar · Multiple Choice Questions
    Aluminium is used for making cooking utensils. ​Which of ​the following properties of aluminium are ​responsible for the ​same?

    1. (i)​Good thermal conductivity
    2. (ii)Good electrical ​conductivity
    3. (iii)Ductility
    4. (iv)​High ​melting point

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

    (d) (i) and (iv)

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15. Q35 Exemplar · Multiple Choice Questions
    Which one of the following metals do ​not react with cold as well as ​hot ​water?

    1. (a)$\text{Na}$
    2. (b)$\text{Ca}$
    3. (c)$\text{Mg}$
    4. (d)$\text{Fe}$
    Show answer

    (d) $\text{Fe}$

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16. Q36 Exemplar · Multiple Choice Questions
    Which of the following oxide(s) of iron ​would be ​obtained ​on prolonged ​reaction of ​iron ​with steam?

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

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17. Q37 Exemplar · Multiple Choice Questions
    What ​happens when ​calcium is treated with ​water?

    1. (i)It does not react ​with water
    2. (ii)It reacts violently with water
    3. (iii)It reacts ​less violently ​with water
    4. (iv)Bubbles of hydrogen gas formed stick to the surface of calcium

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

    (d) (iii) and (iv)

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18. Q38 Exemplar · Multiple Choice Questions
    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 $\text{Mn}$ and $\text{Mg}$)?

    1. (a)${\text{H}}_2{\text{SO}}_4$
    2. (b)$\text{HCl}$
    3. (c)${\text{HNO}}_3$
    4. (d)All of these
    Show answer

    (c) ${\text{HNO}}_3$

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19. Q39 Exemplar · Multiple Choice Questions
    The ​composition ​of ​aqua-regia is

    1. (a)Dil. $\text{HCl}$ : Conc. ${\text{HNO}}_3$ as $3:1$
    2. (b)Conc. $\text{HCl}$ : Dil. ${\text{HNO}}_3$ as $3:1$
    3. (c)Conc. $\text{HCl}$ : Conc. ${\text{HNO}}_3$ as $3:1$
    4. (d)Dil. $\text{HCl}$ : Dil. ${\text{HNO}}_3$ as $3:1$
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    (c) Conc. $\text{HCl}$ : Conc. ${\text{HNO}}_3$ as $3:1$

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20. Q40 Exemplar · Multiple Choice Questions
    Which of ​the following are ​not ​ionic ​compounds?

    1. (i)$\text{KCl}$
    2. (ii)$\text{HCl}$
    3. (iii)${\text{CCl}}_4$
    4. (iv)$\text{NaCl}$

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

    (b) (ii) and (iii)

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