For a reaction $\mathrm{A}(\mathrm{g})+\frac{1}{2} \mathrm{~B}(\mathrm{~g}) \rightleftharpoons…
For a reaction
$\mathrm{A}(\mathrm{g})+\frac{1}{2} \mathrm{~B}(\mathrm{~g}) \rightleftharpoons \mathrm{C}(\mathrm{g})+$ heat
favorable conditions for the reaction to occur in the forward direction are
Low $\mathrm{T}$ and Low $\mathrm{P}$
Low $\mathrm{T}$ and high $\mathrm{P}$
High $T$ and Low $P$
High $\mathrm{T}$ and high $\mathrm{P}$
Solution
$\mathrm{A}(\mathrm{g})+\frac{1}{2} \mathrm{~B}(\mathrm{~g}) \rightleftharpoons \mathrm{C}(\mathrm{g})+$ heat
exothermic reaction
$\therefore \quad$ Low temperature is favourable.
$\Delta \mathrm{n}=-1-\left(1+\frac{1}{2}\right)=1-\frac{3}{2}=-\frac{1}{2}$
no. of gas molecules decreases in the forward reaction.
So, high pressure is favourable for forward reaction.