Ostwald Process (Produces Nitric Acid)

At the first stage, ammonia is oxidized in excess in the presence of platinum as catalyst to produce nitrogen monoxide. The high temperature of 850°C and pressure of 5 atmospheres is used
4NH 3 ( g )  +  5O 2(g) 4NO (g) +  6H 2 O (1)
Nitrogen monoxide that is formed reacts with oxygen to produce nitrogen dioxide at stage two.
2NO (g) +  O 2 2NO 2
At the final stage, nitrogen dioxide together with excess air is dissolved in hot water at a temperature of 80°C to produce concentrated nitric acid.
4NO 2(g) +  O 2(g) +  2H 2 O (1) 4HNO 3(g)