Which term describes the chemical equilibrium between a forward reaction and the reverse reaction where the rates are equal?

• A. Dynamic equilibrium
• B. Static equilibrium
• C. Equilibrium constant
• D. Le Chatelier's principle

Answer: (A)

Dynamic equilibrium is the best description because it captures the idea that the forward and reverse reaction rates are equal, so the amounts of reactants and products stay constant over time while the reactions continue to occur in both directions. This ongoing activity is what makes it dynamic, not static. If the system were static equilibrium in the chemical sense, there would be no ongoing change at all, which isn’t the case for reversible reactions. The equilibrium constant describes the relationship of concentrations at equilibrium, not the fact that the two rates are equal, and Le Chatelier's principle explains how shifting conditions changes the position of equilibrium rather than defining the state itself.