Question

Question 44

You are provided with two containers made up of copper and aluminium. You are also provided with solutions of dilute $\text{HCl}$, dilute ${\text{HNO}}_3,{\text{ZnCl}}_2\text{(aq)}$ and ${\text{H}}_2\text{O}$. In which of the above containers these solutions can be kept?

Answer 1

A) Copper container

(a) Dilute $\text{HCl}$: Copper does not react with dilute $\text{HCl}$. Therefore, it can be kept.

(b) Dilute ${\text{HNO}}_3$: Nitric acid acts as a strong oxidizing agent and reacts with copper vessel, therefore it cannot be kept.

$3\text{Cu(s)}+8{\text{HNO}}_3\text{(aq)}\to 3{\text{Cu(NO}}_3{)}_2\text{(aq)}+2\text{NO(g)}+4{\text{H}}_2\text{O(l)}$

(c) ${\text{ZnCl}}_2$: Zinc is more reactive than copper $\text{Cu}$, i.e., copper cannot displace zinc from its solution, therefore, no displacement reaction occurs and hence ${\text{ZnCl}}_2$ can be kept.

(d) ${\text{H}}_2\text{O}$: Copper does not react with water. Therefore, can be kept.

(B) Aluminium container

(a) Dilute $\text{HCl}$: Aluminium reacts with dilute $\text{HCl}$ to form its salt and hydrogen gas is evolved. Therefore, it cannot be kept.

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

(b) Dilute ${\text{HNO}}_3$: Aluminium gets oxidised by dilute ${\text{HNO}}_3$ to form a layer of ${\text{Al}}_2{\text{O}}_3$. Therefore, it cannot be kept.

(c) ${\text{ZnCl}}_2$: Aluminium being more reactive than zinc can displace zinc from the solution. Therefore, the solution cannot be kept.

$2\text{Al (s)}+3{\text{ZnCl}}_2\text{(aq)}\to 2{\text{AlCl}}_3\text{(aq)}+3\text{Zn(s)}$

(d) ${\text{H}}_2\text{O}$: Aluminium does not react with cold or hot water. It is attacked by steam to form aluminium oxide and hydrogen gas. Therefore, water can be kept.

$2\text{Al (s)}+3{\text{H}}_2\text{O (g)}\to {\text{Al}}_2{\text{O}}_3\text{(s)}+3{\text{H}}_2\text{(g)}$