Which of the following statements about an equilibrium system is correct?

An equilibrium system refers to a state where the rates of forward and backward reactions are equal. Therefore, the statement that is correct is "Forward and backward reactions occur at the same rate". The other options are incorrect because: - The concentrations of reactants and products are not necessarily equal at equilibrium. The actual concentrations depend on the equilibrium constant and the initial concentrations of the reactants and products. - The addition of a catalyst only affects the rate of the reaction, but not the position of equilibrium or the concentrations of the reactants and products at equilibrium. - Changes in temperature can affect the position of equilibrium and the concentrations of the reactants and products at equilibrium.