ICSE Class 10 Answered

Haber's process is an industrial or commercial process used for the manufacture of ammonia. This method is carried out from nitrogen and hydrogen using iron catalyst at 400-450 degree Celsius and 200 atmospheres pressure on a large scale. 

THE PROCESS

The Haber process takes nitrogen gas from air and combines it with molecular hydrogen gas to form ammonia gas. This is an exothermic reaction, meaning it releases energy so that the sum of the enthalpies of N₂ and H₂ (the reactants) is greater than the enthalpy of NH₃ (the products).

A mixture of hydrogen and nitrogen gases in the ratio 3:1 is taken in compressor. It is then compressed to about 200 atm pressure and passed over heated catalyst in catalyst chamber. The mixture ismaintained at a temperature between 400 - 445⁰C. In condenser, the hot mixture of ammonia gas and unreacted hydrogen and nitrogen gases coming out of catalyst chamber are led to the cooling pipes.

N₂(g) + 3H₂(g) → 2NH₃(g)     ΔH = - 92.4 kJ

Which is a reversible reaction:

2NH₃(g) → N₂(g) + 3H₂(g)     ΔH = + 92.4 kJ mol^-1

The unused mixture of hydrogen and nitrogen gases are recompressed and then recycled into catalyst chamber.