KCET 2026 Chemistry Solved Paper

Concept:Le Chatelier's principle states that changing temperature or pressure shifts equilibrium to oppose the change.Explanation:The reaction is$$3\mathrm{A}_{(g)} + \mathrm{B}_{(g)} \rightleftharpoons \mathrm{A}_3\mathrm{B}_{(g)}$$Given $\Delta_r H = -q\ \mathrm{kJ}$, the forward reaction is exothermic.Effect of temperature:Increasing temperature favours the backward (endothermic) reaction, so the amount of $\mathrm{A}_3\mathrm{B}$ decreases.Decreasing temperature favours the forward (exothermic) reaction, so the amount of $\mathrm{A}_3\mathrm{B}$ increases.Hence temperature affects the amount of product.Effect of pressure:Reactant side gaseous moles $= 3 + 1 = 4$.Product side gaseous moles $= 1$.Increasing pressure shifts equilibrium towards the side with fewer gaseous moles, which is the product side.Therefore, pressure also affects the amount of $\mathrm{A}_3\mathrm{B}$.A catalyst only speeds up the reaction and does not change the equilibrium amount.Answer:The amount of $\mathrm{A}_3\mathrm{B}_{(g)}$ is affected by both temperature and pressure.Correct option: C. Both temperature and pressure