Question

Question 59
A non-metal A, which is the largest constituent of air, when heated with ${\text{H}}_2$ in 1:3 ratio in the presence of catalyst $\text{Fe}$, gives a gas B.
On heating with ${\text{O}}_2$, it gives an oxide C. If this oxide is passed into water in the presence of air it gives an acid D, which acts as a strong oxidising agent.

(a) Identify A, B, C and D
(b) To which group of periodic table does this non-metal belong?

Answer 1

(a) Nitrogen is the largest constituent of air. So, A is nitrogen.
When it is heated with hydrogen in 1:3 ratio in the presence of iron as the catalyst, it forms ammonia. So, B is ammonia. The reaction occurs as follows:

${\text{N}}_2\text{(g)}+3{\text{H}}_2\text{(g)}\stackrel{\text{Fe}}{⟶}2{\text{NH}}_3\text{(g)}$

When nitrogen is heated with oxygen it forms nitrous oxide, so C is nitrous oxide. the reaction involved is:

${\text{N}}_2\text{(g)}+{\text{O}}_2\text{(g)}\to 2\text{NO(g)}$

Again when nitrogen oxide is passed into water in presence of air it forms nitric acid. So, D is ${\text{HNO}}_3$. The reaction involved is:

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

Nitric acid is a strong oxidising agent.

(b) Element A, i.e., nitrogen belongs to Group 15 of the periodic table.