Question

The Haber's process is carried out at high temperature even though the equilibrium constant for the reaction decreases with increasing temperature. Explain, why a high temperature is necessary?

Answer 1

The forward reaction in the Haber process is exothermic. This means that if the temperature is increased, the position of equilibrium moves in the direction of the reverse reaction, and less ammonia is formed.

You might think that a low temperature would be a good choice for the Haber process. If the forward reaction is exothermic, the yield of product at equilibrium is increased at lower temperatures. However, if the temperature is too low, the rate of reaction will be too low. This would make the process uneconomical. So a compromise temperature is chosen, low enough to get a good yield of ammonia but high enough to obtain a reasonable rate of reaction.