Question

Question 41

What happens when a piece of

(a) zinc metal is added to copper sulphate solution?

(b) aluminium metal is added to dilute hydrochloric acid?

(c) silver metal is added to copper sulphate solution?

Also, write the balanced chemical equation if the reaction occurs.

Answer 1

(a) Zinc being more reactive than copper displaces it from its solution and a solution of zinc sulphate is obtained.

$\text{Zn(s)}+{\text{CuSO}}_4\text{(aq)}\to {\text{ZnSO}}_4\text{(aq)}+\text{Cu(s)}$

This is an example of displacement reaction.

(b) Aluminium being more reactive than hydrogen displaces it from dilute hydrochloric acid solution and hydrogen gas is evolved.

$\text{2Al(s)}+6\text{HCl (aq)}\to 2{\text{AlCl}}_3\text{(aq)}+3{\text{H}}_2\text{(g)}$

(c) Silver metal being less reactive than copper cannot displace it from its salt solution. Therefore, no reaction occurs.