Question

Question 42
What happens when zinc granules are treated with dilute solution of ${\text{H}}_2{\text{SO}}_4,\text{HCl},{\text{HNO}}_3$, $\text{NaCl}$ and $\text{NaOH}$?
Also write the chemical equations if reaction occurs.

Answer 1

The reaction of $\text{Zn}$ granules with

(a) Dilute ${\text{H}}_2{\text{SO}}_4$: Zinc granules react with dilute sulphuric acid to form zinc sulphate and hydrogen gas. The reaction occurs as follows:

$\text{Zn(s)}+{\text{H}}_2{\text{SO}}_4\text{(aq)}\to {\text{ZnSO}}_4\text{(aq)}+{\text{H}}_2\text{(g)}$

(b) Dilute $\text{HCl}$: Zinc granules react with dilute hydrochloric acid to form zinc chloride and hydrogen gas. The reaction occurs as follows:

$\text{Zn(s)}+2\text{HCl(aq)}\to {\text{ZnCl}}_2\text{(aq)}+{\text{H}}_2\text{(g)}$

(c) Dilute ${\text{HNO}}_3$: As nitric acid is an oxidising agent and it oxidises the evolved ${\text{H}}_2$ gas to ${\text{H}}_2\text{O}$. The reaction occurs as follows:

$4\text{Zn(s)}+10{\text{HNO}}_3\text{(aq)}\to 4{\text{Zn(NO}}_3{)}_2\text{(aq)}+5{\text{H}}_2\text{O(l)}+{\text{N}}_2\text{O(g)}$

(d) $\text{NaCl}$ solution: Zinc granules won't react with $\text{NaCl}$ solution.

(e) $\text{NaOH}$ solution: Zinc granules react with sodium hydroxide to form sodium zincate and hydrogen gas. The reaction occurs as follows:

$\text{Zn(s)}+2\text{NaOH (aq)}\to {\text{Na}}_2{\text{ZnO}}_2\text{(aq)}+{\text{H}}_2\text{(g)}$