Import Question JSON

$\text{Hint: Follow Le Chatelier's principle}$ $\text{PCl}_5\text{(g)} \rightleftharpoons \text{PCl}_3\text{(g)} + \text{Cl}_2\text{(g)}$ $\text{Equilibrium moles: (a-x) \quad x \quad x}$ $\text{The addition of inert gas at constant V has no effect on reactions having } \Delta n = 0 \text{ or } \Delta n \neq 0. \text{ But the addition of inert gas at constant P has an effect on reactions having } \Delta n \neq 0, \text{ and no effect if } \Delta n = 0. \text{ The given reaction has } \Delta n \neq 0 \text{ and thus, only choice (c) is correct.}$ $\text{Analysis of each option:}$ $\text{Option 1: Inert gas at constant volume}$ $\text{• No effect on equilibrium because partial pressures remain unchanged}$ $\text{• Total pressure increases but individual concentrations stay the same}$ $\text{Option 2: Adding Cl}_2 \text{ at constant volume}$ $\text{• Increases [Cl}_2\text{] → shifts equilibrium backward (Le Chatelier's principle)}$ $\text{• Does not favor forward reaction}$ $\text{Option 3: Inert gas at constant pressure}$ $\text{• Volume must increase to maintain constant pressure}$ $\text{• Effectively decreases pressure of reacting gases}$ $\text{• For } \Delta n > 0 \text{ (1 → 2 moles), lower pressure favors forward reaction}$ $\text{• This favors the forward reaction}$ $\text{Therefore, introducing an inert gas at constant pressure favors the forward reaction.}$