Catalysts can influence the stoichiometric ratios by altering the reaction mechanism. For example, in the Haber-Bosch process for ammonia synthesis (N2 + 3H2 → 2NH3), the presence of an iron catalyst enables the reaction to proceed at a lower temperature and pressure than would be required otherwise. The catalyst helps in breaking the strong nitrogen triple bond, thus facilitating the reaction at the stoichiometric ratio of 1:3 for nitrogen to hydrogen.
