What occurs in a reversible chemical reaction taking place in a closed system?

In a reversible chemical reaction occurring in a closed system, the correct scenario is the establishment of chemical equilibrium. At equilibrium, the rates of the forward and reverse reactions are equal, leading to no net change in the concentration of reactants and products over time. This means that while reactions continue to occur, the amounts of each component remain constant.

In a closed system, no substances are added or removed, which allows for this balance to be maintained, resulting in dynamic equilibrium. This is essential in understanding how chemical reactions can reach a state where the concentrations of reactants and products do not change, even though the reactions themselves are still occurring.

The other options do not accurately describe the nature of reversible reactions in a closed system. For instance, while there are changes in concentration that become constant at equilibrium, the system does not lead to complete conversion to products or only forward reactions. Therefore, recognizing that a reversible chemical reaction in a closed system results in chemical equilibrium is fundamental to grasping the behavior of such reactions.