Name three oxoacids of nitrogen. Write the disproportionation reaction of that oxoacid of nitrogen in which nitrogen is in $(+3)$ oxidation state.

(N/A) Three oxoacids of nitrogen are:
$(i)$ Nitrous acid - $HNO_2$
$(ii)$ Nitric acid - $HNO_3$
$(iii)$ Hyponitrous acid - $H_2N_2O_2$
The oxoacid of nitrogen in which nitrogen is in $(+3)$ oxidation state is nitrous acid $(HNO_2)$.
The disproportionation reaction is:
$3HNO_2 \rightarrow HNO_3 + H_2O + 2NO$
In this reaction,the oxidation state of nitrogen changes from $(+3)$ to $(+5)$ in $HNO_3$ and $(+2)$ in $NO$.