Question

Explain the following process -

(a) Ostwald's process

(b) Haber 's process

Answer 1

a) Ostwald process :
This process is used for producing nitric acid (HNO₃ ). When a mixture of ammonia and air is passed through a catalytic chamber containing electrically heated Platinum Gauze, (NO) nitric oxide is formed. This nitric oxide combines with more oxygen to form nitrogen dioxide (NO₂). This gas is then absorbed by water to form nitric acid. The reaction is as follows:

Step -1 2NH₃ + 5[O] → 2NO + 3H₂O

Step -2 2NO + O₂ → 2NO₂

Step-3 4NO₂ + 2H₂O + O₂ → 4HNO₃

b) Haber's process : is used for the manufacture of ammonia. from nitrogen and hydrogen using iron as a catalyst. This process is carried out at 400-450 degree celsius and 200 atmospheric pressure. It is an industrial process.
In this process a mixture of hydrogen and nitrogen gases are in the ratio 3 : 1. is taken in the compressor. It is compressed to about 200 atmospheric pressure and passed over heated catalyst in catalyst chamber .This mixture is maintained at a temperature between 400-450 degree celsius. The hot mixture of ammonia gas and unreacted hydrogen and nitrogen gases in the condensor comes out of the catalyst chamber are then led to cooling pipes.
It is a reversible reaction and exothermic in nature.
N₂ + 3H₂ $\underset{\text{400-450 degree celsius}}{\overset{\text{Fe catalyst, 200 atm}}{\to }}$ 2NH₃
In this reaction, catalyst used is iron oxide with small amount of molybdenum.
Formation of ammonia requires high pressure.