Why does the Haber-Bosch process use high pressure?

The Haber-Bosch process utilizes high pressure because it is essential for maximizing the yield of ammonia during the synthesis reaction.

In this chemical process, nitrogen and hydrogen are combined to form ammonia. Because the reaction reaches an equilibrium, the specific conditions under which it is conducted determine the final proportion of the product. According to the principles of chemical equilibrium, increasing the pressure shifts the reaction toward the side that occupies less volume, thereby favoring the formation of ammonia. Consequently, the higher the pressure applied, the greater the proportion of ammonia yielded in the mixture.1

For commercial production, this process is typically carried out at pressures ranging from 200 to 400 atmospheres. By maintaining these high-pressure conditions alongside the use of a catalyst, the process becomes an economically feasible method for the fixation of nitrogen.1