NCERT Solutions for Class 10 Science Chapter 3 Metals and Non-Metals
NCERT Intext Questions
- (i) is a liquid at room temperature.
- (ii) can be easily cut with a knife.
- (iii) is the best conductor of heat.
- (iv) is a poor conductor of heat.
- Ans. (i) Mercury
- (ii) Sodium
- (iii) Silver
- (iv) Lead
(i) iron with steam,
(ii) calcium and potassium with water.
Ans. $$\text{(i)}\space 3Fe(s) + \underset{\text{Steam}}{4H_2O(g)} → \underset{\text{Iron (II, III) oxide}}{Fe_3O_4(s)} + 4H_2(g) \\ \text{(ii)}\space Ca(s) + 2H_2O(l) → \underset{\text{Calcium hydroxide}}{Ca(OH)_2(aq)} + H_2(g) \\ \space 2K(s) + \underset{\text{Cold}}{2H_2O(l)} → \underset{\text{Potassium hydroxide}}{2KOH(aq)} + H_2(g)+ \text{Heat}$$
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 |
(i) Which is the most reactive metal ?
(ii) What would you observe if B is added to a solution of copper (II) sulphate?
(iii) Arrange the metals A, B, C and D in the order of decreasing reactivity.
(ii) When metal B is added to copper (II) sulphate solution, a displacement reaction will take place due to which the blue colour of copper (II) sulphate solution will fade and a red-brown deposit of copper will be formed on metal B.
(iii) Metal B is the most reactive because it displaces iron from its salt solution. Metal A is less reactive because it displaces copper from its salt solution. Metal C is still less reactive because it can displace only silver from its salt solution and metal D is the least reactive because it cannot displace any metal from its salt solution. Hence, the decreasing order of reactivity of the metals is B > A > C > D.
Fe (s) + H2SO4 (aq) → FeSO4 (aq) + H2 (g)
(ii) Show the formation of Na2O and MgO by the transfer of electrons.
(iii) What are ions present in these compounds?
Element | Sodium (Na) | Oxygen (O) | Magnesium (Mg) |
Electron dot structure | $$\underset{\text{2,8,1}}{\text{\.{Na}}}$$ | $$\underset{\text{2,8,6}}{\underset{\text{\" }}{\cdot \text{\"{O}}\cdot}}$$ | $$\underset{\text{2, 8, 2}}{\ddot Mg}$$ |

In MgO, ions present are Mg2+ (cation) and O2– (anion).
Page Number 53
(i) Mineral
(ii) Ore and
(iii) Gangue
(ii) Ore: The mineral from which metal can be profitably extracted is called an ore.
(iii) Gangue: Ores mined from the earth are usually contaminated with large amounts of impurities such as soil, sand, etc. These impurities are called as gangue.
In this reaction zinc oxide is reduced by carbon on heating at high temperature to get zinc metal.
Page Number 55
Metal | Zinc | Magnesium | Copper | |
1. | Zinc oxide | |||
2. | Magnesium oxide | |||
3. | Copper oxide |
The displacement will take place in the following cases:
Metal | Zinc | Magnesium | Copper | |
1. | Zinc oxide | - | Displacement | - |
2. | Magnesium oxide | - | - | - |
3. | Copper oxide | Displacement | Displacement | - |
NCERT Exercise Questions
(a) NaCl solution and copper metal
(b) MgCl2 solution and aluminium metal
(c) FeSO4 solution and silver metal
(d) AgNO3 solution and copper metal
Explanation: In displacement reaction highly reactive metal displaces less reactive metal.
Cu is less reactive than Na so it cannot displace Na.
Al is less reactive than Mg so it cannot displace Mg.
Ag is less reactive than Fe so it cannot displace Fe.
Cu is more reactive than Ag so it will displace Ag and form CuNO3.
(a) Applying grease
(b) Applying paint
(c) Applying a coating of zinc
(d) All the above
Explanation: We can prevent iron getting rusted by applying a coat of zinc or a thin coat of plastic helps to prevent rust. The process for coating metal like iron or steel with a thin zinc layer is known as galvanization.
3. An element reacts with oxygen to give a compound with a high melting point. This compound is also soluble in water. The element is likely to be
(a) Calcium
(b) Carbon
(c) Silicon
(d) Iron
Explanation: Ca reacts with oxygen to form CaO which has high melting point and is soluble in water.
(a) zinc is costlier than tin
(b) zinc has a higher melting point than tin
(c) zinc is less reactive than tin
(d) zinc is more reactive than tin.
Explanation: Food cans are coated with tin and not with zinc because zinc is more reactive than tin and it may react with preserved food items.
(a) How could you use them to distinguish between samples of metals and non-metals?
(b) Assess the usefulness of these tests in distinguishing between metals and non-metals.
Metals are malleable in nature i.e., when beaten with hammer it will be converted into thin sheets without breaking whereas non-metals are non-malleable i.e., brittle i.e., when beaten with hammer it will break into pieces.
Metals are good conductor of electricity because of presence of free electrons whereas non-metals are not good conductor of electricity. So, when metals are connected into circuit using battery bulb, wire and switch, current passes through the circuit and the bulb glows and when the non-metals are connected in circuit, bulb does not glow.
(b) Useful of these tests is because of malleability, metals can be casted into sheets. Metals are good conductors of electricity so these can be used for manufacturing electrical cables.
Examples: Sodium and Potassium
(ii) Metals which are less reactise than hydrogen cannot displace hydrogen from dilute acids.
Example: Copper or silver.
(ii) Anode – Impure metal
(iii) Electrolyte – Metal salt solution
During electrolytic refining of a metal, impure metal is used as anode and a pure metal is used as cathode and metal salt solution is used as electrolyte.
(a) What will be the action of gas on
(i) dry litmus paper ?
(ii) moist litmus paper ?
(b) Write a balanced chemical equation for the reaction taking place.

(i) There will be no action on dry litmus paper as both litmus paper and gas lack moisture (H2O).
(ii) The colour of moist litmus paper will turn red because when SO2 gas reacts with moisture (H2O), it will form H2SO4 which is an acid.
(b) Balanced chemical equation: $$\underset{\text{Sulphur}}{S} + \underset{\text{Oxygen}}{O_2} → \underset{\text{Sulphur dioxide}}{SO_2}$$
(a) Platinum, gold and silver are used to make jewellery.
(b) Sodium, potassium and lithium are stored under oil.
(c) Aluminium is a highly reactiv e metal, yet it is used to make utensils for cooking.
(d) Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
(b) Sodium, potassium and lithium are very reactive and catch fire when exposed to air. This is due to their low ignition temperature and high reactivity.
(c) Aluminium forms a non-reactive layer of aluminium oxide on its surface. This layer prevents aluminium to react with other substances. That is why aluminium is used to make cooking utensils.
(d) It is easier to reduce a metal oxide into free metal. Since it is easier to obtain metals from their oxides than from their carbonates or sulphides directly, therefore, the carbonate and sulphide ores are first converted to oxides for extracting the metals.
13. You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Metal | Non-metals | |
(i) | Metals react with oxygen to form basic oxides. 4NO + O2 → 2Na2O | Non-metals react with oxygen to form acidic or neutral oxide. C + O2 → CO2 |
(ii) | Metals react with water to form hydroxide and hydrogen. 2Na + H2O → 2NaOH + H2 | Generally non-metals do not react with water. |
(iii) | Metals are electropositive. | Non-metals are electronegative. |
(iv) | Metals displace hydrogen from dilute acid and form salts. | Non-metals do not displaces hydrogen from dilute acid. |
(i) Copper does not react with water whereas steel reacts with water easily and thus corrodes.
(ii) Copper is unaffected by change in temperature whereas steel is influenced by steam.