ICSE Class 10 Answered

The Haber process, also known as the Haber-Bosch Process, was founded by Fritz Haber and Carl Bosch, both who were German Chemists. Haber discovered the conditions for the formation of ammonia, and Bosch discovered the work of high-pressure on chemical reactions (developed into industrial process). Both were awarded the Nobel Prize.

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).

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

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 is maintained at a temperature between 400 45⁰C. 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

Here's a visual to help convey the process:

Catalysts such as iron oxide with small amounts of Al₂O₃ and K₂O are used to increase the rate of attainment of equilibrium.

High pressure favors the formation of NH₃ .

Optimum condition: Pressure = 200 × 10⁵ Pa (about 200 atm)

Temperature = 700 K

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