WAEC Chemistry 2022 Paper

Concept:Dynamic equilibrium is reached when the forward and backward reactions take place at the same rate.Explanation:In an equilibrium system, the reaction is dynamic and both the forward and backward reactions continue to occur.Equilibrium is established when the rate of the forward reaction is exactly equal to the rate of the backward reaction.At equilibrium, the concentrations of reactants and products become constant, but they do not have to be equal to each other.Adding a catalyst speeds up both the forward and backward reactions equally, so it does not shift the position of equilibrium or change the concentrations.A change in temperature does affect the equilibrium position, so the concentrations of reactants and products will change accordingly.Thus, the only correct statement is that the forward and backward reactions occur at the same rate.Answer:Option A — Forward and backward reactions occur at the same rate.