$1.\,\,\,4\mathop N\limits^{ - 3} {H_3} + 5{O_2} \to 4\mathop N\limits^{ + 2} \mathop O\limits^{ - 2} + 6{H_2}\mathop O\limits^{ - 2}$
\[\begin{gathered} 4x\,\,\,\,\,\,\,{N^{ - 3}} \to {N^{ + 2}} + 5e \hfill \\ 5x\,\,\,\,\,\,{O_2} + 4e \to 2{O^{ - 2}} \hfill \\ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ \hfill \\ 4{N^{ - 3}} + 5{O_2} \to 4{N^{ + 2}} + 10\,\,{O^{ - 2}} \hfill \\ \end{gathered} \]
$2.\,\,Fe{S_2} + 8HN{O_3} \to Fe{(N{O_3})_3} + 2{H_2}S{O_4} + 5NO + 2{H_2}O$
$1x\,\,\,\,\,\,\,{(Fe{S_2})^0} \to F{e^{3 + }} + 2{S^{ + 6}} + 15e $
$ 5x\,\,\,\,\,\,\,{N^{ + 5}} + 3e \to {N^{ + 2}} $
$ \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ $
$ Fe{S_2} + 5{N^{ + 5}} \to F{e^{3 + }} + 2{S^{ + 6}} + 5{N^{ + 2}} $
