Question

How is nitric acid manufactured from NH3 ?

Answer 1

Nitric acid is most commonly manufactured by Ostwald process. The Ostwald process converts ammonia to nitric acid and involves two steps.

In step 1, ammonia is oxidized to form nitric oxide and also nitrogen dioxide.
4NH3 + 5O2 ↔ 4NO + 6H2O


Then in step 2, the nitrogen dioxide that was formed is absorbed in water. This in-turn forms nitric acid.
2NO + O2 ↔2 NO2


Step 3 - Absorption of NO2 (formation of HNO3)
3NO2 + H2O -> 2HNO3 + NO

Step 4 - Concentration