In dynamic equilibrium, which statement is true?

In dynamic equilibrium, which statement is true?

• A. The forward and reverse reaction rates are equal
• B. The concentrations of all species are equal
• C. No molecules react at all
• D. The reaction is complete and stops

Answer: (A)

Dynamic equilibrium is reached when the forward and reverse reaction rates are equal, so there is no net change in the concentrations of reactants and products over time. Even though the two reactions keep happening, their rates balance so the overall amounts stay constant. The concentrations of individual species don’t have to be equal to one another; they settle at fixed values determined by the equilibrium constant. The system is not “stopped” or finished—molecules still react in both directions, just at equal speeds, which is what maintains the constant composition. The idea that no molecules react at all or that the reaction is complete and stops would describe a finished reaction, not dynamic equilibrium.

Dynamic equilibrium is reached when the forward and reverse reaction rates are equal, so there is no net change in the concentrations of reactants and products over time. Even though the two reactions keep happening, their rates balance so the overall amounts stay constant. The concentrations of individual species don’t have to be equal to one another; they settle at fixed values determined by the equilibrium constant. The system is not “stopped” or finished—molecules still react in both directions, just at equal speeds, which is what maintains the constant composition. The idea that no molecules react at all or that the reaction is complete and stops would describe a finished reaction, not dynamic equilibrium.