WAEC Chemistry 2015 Paper

Concept:According to Le Chatelier’s principle, adding a reactant shifts the equilibrium in the direction that consumes the added substance.Explanation:The given equilibrium is:$$2\mathrm{SO}_{2(g)} + \mathrm{O}_{2(g)} \rightleftharpoons 2\mathrm{SO}_{3(g)}$$Adding more $\mathrm{O}_{2(g)}$ increases the concentration of a reactant.To reduce this disturbance, the system favours the forward reaction, which uses up $\mathrm{O}_{2(g)}$.As a result, more $\mathrm{SO}_{2(g)}$ reacts to form additional $\mathrm{SO}_{3(g)}$.Therefore, the equilibrium position shifts to the right.Answer:Right, leading to the production of more $\mathrm{SO}_{3(g)}$.