In dynamic equilibrium, forward and reverse reactions occur at the same rate.

In dynamic equilibrium, forward and reverse reactions occur at the same rate.

• A. The forward and reverse reactions occur at the same rate.
• B. The forward reaction occurs faster than the reverse.
• C. The concentrations of products remain unchanged.
• D. The system eventually reaches a state with no further change in concentrations.

Answer: (A)

In dynamic equilibrium, the defining feature is that the forward and reverse reaction rates are equal. When those rates match, there is no net change in the concentrations of reactants and products over time, even though molecules continue to react in both directions. The actual amounts present at equilibrium depend on the temperature and the equilibrium constant, not on the rates alone. If the forward rate were faster than the reverse, the system would keep producing more products until the rates balance, so that scenario isn’t equilibrium. Saying the concentrations of products remain unchanged is a consequence of the rate balance, but it doesn’t by itself specify why that happens. And the idea of no further change in concentrations might imply no reactions are occurring, which isn’t true—the two opposing processes continue at the same rate, giving no net change.

In dynamic equilibrium, the defining feature is that the forward and reverse reaction rates are equal. When those rates match, there is no net change in the concentrations of reactants and products over time, even though molecules continue to react in both directions. The actual amounts present at equilibrium depend on the temperature and the equilibrium constant, not on the rates alone. If the forward rate were faster than the reverse, the system would keep producing more products until the rates balance, so that scenario isn’t equilibrium. Saying the concentrations of products remain unchanged is a consequence of the rate balance, but it doesn’t by itself specify why that happens. And the idea of no further change in concentrations might imply no reactions are occurring, which isn’t true—the two opposing processes continue at the same rate, giving no net change.