Q.

Production of ammonia according to the reaction,N2(g)+3H2(g)⇌2NH3(g)                                   ΔH=-92.38 kJ mol-1is an exothermic process. According to Le-Chatelier's principle, raising the temperature, shifts the equilibrium to left and decreases the equilibrium concentration of ammonia. In other words, low temperature is favourable for high yield of amrnonia, but practically very low temperatures slow down the reaction and thus a catalyst is used.