Industrially ammonia is manufactured by Haber’s process. $\mathrm{N}_{2(\mathrm{g})}+3\mathrm{H}_{2(\mathrm{g})}\rightarrow2\mathrm{NH}_{3(\mathrm{g})};$ $\Delta_f H^\circ = -46.1\ \text{kJ/mol}$ In accordance with Le-Chatelier’s principle, high pressure and lowtemperature would favourthe formation of ammonia. The optimumconditions for production of ammonia are a pressure of 200 × 10$^{5}$Pa(about 200 atm), a temperature of ~700 K and the use of a catalyst suchas iron-oxide with small amounts of $\mathrm{K}_2\mathrm{O}$ and $\mathrm{Al}_2\mathrm{O}_3$ to increase therate ofattainment of equilibrium.