Question

In which reaction does nitrogen exhibit variation of oxidation state from –3 to +5?

Answer 1

In the following series of reactions, the oxidation number of nitrogen changes from –3  in NH₃ to +5 in HNO₃.

\[\ce{\underset{\text{Ammonia}}{\overset{-3}{4NH3}}_{(g)} + \underset{\text{Oxygen}}{5O2}_{(g)}->[Pt/Rhgauge catalyst][500K,9 bar]\underset{\text{Nitric oxide}}{\overset{+2}{4NO}}_{(g)} + 6H2O_{(g)}}\]

\[\ce{\underset{\text{Nitric oxide}}{2NO}_{(g)} + \underset{\text{Oxygen}}{O2}_{(g)}⇌\underset{\text{Nitrogen dioxide}}{\overset{+4}{2NO2}}_{(g)}}\]

\[\ce{\underset{\text{Nitrogen dioxide}}{3NO2}_{(g)} + \underset{\text{Water}}{H2O}_{(l)}->\underset{\text{Nitric acid}}{\overset{+5}{2HNO3}}_{(l)} + \underset{\text{Nitric oxide}}{NO}_{(g)}}\]