In a closed system, equilibrium is said to be dynamic. why? a. the forward and reverse reactions stop. b. the reverse reaction goes to completion. c. the forward reaction goes to completion. d. the forward and reverse reactions continue indefinitely.

A dynamic equilibrium is a state of equilibrium that occurs when two opposing forces reach a state of balance. This means that the two opposing forces occur at the same rate.

Applying this to a closed system of reversible reaction, the two opposing forces would be the forward and the backward reaction. The dynamic state of equilibrium is reached when they both occur indefinitely at the same rate.

Based on this, the right choice would be:
D. The forward and reverse reactions continue indefinitely