(N/A) Ammonia is prepared using the Haber's process. The reaction is given by: $N_{2}(g) + 3H_{2}(g) \rightleftharpoons 2NH_{3}(g); \Delta H = -92.4 \, kJ \, mol^{-1}$.
The yield of ammonia can be maximized under the following conditions:
$(i)$ High pressure: $A$ pressure of $\sim 200 \, atm$ is used to shift the equilibrium towards the product side as there is a decrease in the number of moles.
$(ii)$ Optimum temperature: $A$ temperature of $\sim 700 \, K$ is used. Although the reaction is exothermic,this temperature is a compromise to ensure a reasonable rate of reaction.
$(iii)$ Catalyst: Use of a catalyst such as iron oxide mixed with small amounts of $K_{2}O$ and $Al_{2}O_{3}$ to increase the rate of attainment of equilibrium.