Question

Nitrogen forms largest oxides as it is capable of forming stable multiple bonds with oxygen. They range from $N_{2}O$ (O.S of nitrogen +1) through $NO,N_2{O}_3,N_2{O}_4$ to $N_2{O}_5$ (O.S of nitrogen +5).

The following points are important regarding the oxides of nitrogen.

(a) All oxides of nitrogen except $N_2{O}_5$ are endothermic because large amount of energy is required to dissociate the stable molecule of oxygen and nitrogen.

(b) The small electronegativity difference between oxygen and nitrogen makes N-O bond easily breakable to give oxygen and hence oxides of nitrogen are said to be better oxidizing agents.

(c) Except $N_2{O}_5$, all are gases at ordinary temperature. $N_2{O}_3$ is stable only at a lower temperature (253 K).

(d) Except $N_{2}O$ and $NO$ which are neutral oxides, all are acidic oxides that dissolve in water forming corresponding oxyacids.

(e) They are also a good example of illustrating the concept of resonance.

The gas which is acidic in nature is ________.

• A. $NO$
• B. $N_{2}O$
• C. $N{O}_2$
• D. Both (A) and (C)

Answer 1

The correct option is C $N{O}_2$

Nitrogen dioxide is an acidic gas. $N{O}_2$ dissolves in water and reacts with water to give nitrous acid and nitric acid.

$H_{2}O+2N{O}_2\to HN{O}_3+HN{O}_2$

$N{O}_2$ is also considered as mixed anhydride because it gives both $HN{O}_2$ and $HN{O}_3$ as shown in the above reaction.