equilibrium. This change in the direction of equilibrium is governed by Le-Chatelier's principle. According to Le-Chatellier's principle, equilibrium shifts in die opposite direction to undo the change. $\mathrm{N}_{2}(\mathrm{g})+3 \mathrm{H}_{2}(\mathrm{g}) \rightleftharpoons 2 \mathrm{NH}_{3}(\mathrm{g})+\mathrm{Heat}$

(a) Increasing the concentration of $N H_{3}(g):$ On increasing the concentration of $N H_{3}(g)$. the equilibrium shifts in the backward direction where concentration of $N H_{3}(g)$ decreases

(b) Decreasing the pressure: since, $p \propto n$ (number of moles), therefore, equilibrium shifts in the backward direction where number of moles are increasing.

(c) Decreasing the concentration of $N_{2}(g)$ and $H_{2}(g)$ Equilibrium shifts in the backward direction when concentration of $H_{2}(g)$ and $H_{2}(g)$ decreases.

(d) Increasing pressure and decreasing temperature: On increasing pressure, equilibrium shifts in the forward direction where number of moles decreases. It is an example of exothermic reaction therefore decreasing temperature favours the forward direction