Question

Which of the following statements is/are incorrect?

• A. Ammonia is oxidisied to $N{O}_2$ by oxygen at ${800}^{o}C$ in presence of a catalyst platinum
• B. Nitric acid on standing slowly turns yellow
• C. Colloidal sulphur is formed when $H_{2}S$ gas is passed through nitric acid solution
• D. $N_2{O}_3$ gas dissolves in water giving a pale blue solution

Answer 1

The correct option is A Ammonia is oxidisied to $N{O}_2$ by oxygen at ${800}^{o}C$ in presence of a catalyst platinum

(A) $2N{H}_3+5O_2\underset{{800}^{o}C}{\overset{Pt}{\to }}2NO+3H_{2}O$

(B) Due to the formation of $N{O}_2$, nitric acid on standing turns ywllow according to following reactions.
$3HN{O}_3\to HN{O}_2+2N{O}_2+H_{2}O+O_2$

(C) $H_{2}S+\left[O\right]\to H_{2}O+S;\left[O\right]$ in the reaction is from $HN{O}_3$.

(D) $N_2{O}_3+H_{2}O\to 2HN{O}_2$(pale blue)