Metals and Non Metals

Class 10 NCERT Science

NCERT

1   Give an example of a metal which$\\$ (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.$\\$

Solution :

(i) Metal that exists in liquid state at room temperature $\rightarrow $ Mercury $\\$(ii) Metal that can be easily cut with a knife $\rightarrow $ Sodium$\\$ (iii) Metal that is the best conductor of heat $\rightarrow $ Silver$\\$ (iv) Metals that are poor conductors of heat $\rightarrow $ Mercury and lead

2   Explain the meanings of malleable and ductile.

Solution :

$\text{Malleable:}$ Substances that can be beaten into thin sheets are called malleable. Forexample, most of the metals are malleable.$\\$ $\text{Ductile:}$ Substances that can be drawn into thin wires are called ductile. For example,most of the metals are ductile.

3   Define the following terms.$\\$ (i) Mineral $\\$(ii) Ore $\\$(iii) Gangue

Solution :

(i) $\text{Mineral:}$ Most of the elements occur in nature as in combined state as minerals. The chemical composition of minerals is fixed.$\\$ (ii) $\text{Ore:}$ Minerals from which metals can be extracted profitably are known as ores.$\\$ (iii) $\text{Gangue:}$ The impurities (sand, silt, soil, gravel, etc.) present in the ore are called gangue.

4   Write equations for the reactions of$\\$ (i) iron with steam$\\$ (ii) calcium and potassium with water

Solution :

$\\$(i)$\underset{\text{Iron}}{3Fe_{(s)}}+\underset{\text{Stream}}{4H_2O_{(g)}} \rightarrow \underset{\text{Iron(II,III)oxide}}{Fe_3O_{4(aq)}}+\underset{\text{Hydrogen}}{4H_{2(g)}}$$\\$ $Ca_{(s)}+2H_2O_{(l)}\rightarrow \underset{\text{Iron(II,III)oxide}}{Ca(OH)_{2(aq)}}+\underset{\text{Hydrogen}}{H_{2(g)}}+\text{Heat}$ $\\$ (ii)$\underset{\text{Calcium/Potassium}}{2K_{(s)}}+\underset{\text{Water}}{2H_2O_{(l)}} \rightarrow \underset{\text{Calcium Hydroxide/Potassium Hydroxide}}{2KOH_{(aq)}} +\underset{\text{Hydrogen}}H_{2(g)}+Heat$

5   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. $\\$ $\begin{array}{|c|c|c|c|c|} \hline \textbf{Metal} & \textbf{Iron (II) sulphate} & \textbf{Cooper (II) sulphate } & \textbf{Zinc sulphate }& \textbf{ Silver nitrate} \\ \hline A.& \text{No reaction} &\text{Displacement} & & \\ \hline B.& \text{Displacement} & & \text{No reaction} & \\ \hline C.& \text{No reaction}&\text{No reaction}&\text{No reaction}& \text{Displacement} \\ \hline D. &\text{No reaction}& \text{No reaction} &\text{No reaction}&\text{No reaction} \\ \hline \end{array}$$\\$ Use the Table above to answer the following questions about metals A, B, C and D.$\\$ (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.

Solution :

Explanation:$\\$ $A + FeSO_4 \rightarrow $ No reaction, i.e., A is less reactive than iron$\\$ $A + CuSO_4 \rightarrow $Displacement, i.e., A is more reactive than copper$\\$ $B + FeSO_4 \rightarrow $ Displacement, i.e., B is more reactive than iron$\\$ $B + ZnSO_4 \rightarrow $ No reaction, i.e., B is less reactive than zinc$\\$ $C + FeSO_4 \rightarrow $ No reaction, i.e., C is less reactive than iron$\\$ $C + CuSO _4 \rightarrow $ No reaction, i.e., C is less reactive than copper$\\$ $C + ZnSO_4 \rightarrow $ No reaction, i.e., C is less reactive than zinc$\\$ $C + AgNO_3 \rightarrow $ Displacement, i.e., C is more reactive than silver$\\$ $D + FeSO_4 /CuSO _4 /ZnSO _4 /AgNO _3 \rightarrow $ No reaction, i.e., D is less reactive than iron, copper,zinc, and silver$\\$ From the above equations, we obtain:$\\$ (i) B is the most reactive metal.$\\$ (ii) If B is added to a solution of copper (II) sulphate, then it would displace copper.$\\$ $B + CuSO_4 \rightarrow $ Displacement$\\$ (iii) The arrangement of the metals in the order of decreasing reactivity is: $B > A > C > D$