Hydrogen combines with nitrogen to produce Ammonia in Haber's process. N2(g)+3H2(g)⇌2NH3(g) In this process, iron oxide is used with small amounts of K2O and Al2O3 to increase the rate of attainment of equilibrium. Optimum conditions for the production of ammonia are a pressure of 200 atm and a temperature of 700K. Earlier, iron was used as a catalyst with molybdenum as a promoter in this reaction.