What occurs when a chemical reaction reaches equilibrium?

When a chemical reaction reaches equilibrium, it is characterized by the condition where the rate of the forward reaction equals the rate of the reverse reaction. This means that although the reactions are still occurring, there is no net change in the concentrations of reactants and products over time.

At this stage, the system is in a dynamic balance; molecules of reactants are continually converting into products, while products are simultaneously converting back into reactants. This dynamic but balanced state allows for the concentrations of both reactants and products to remain constant, even though individual molecules are still being transformed.

The other choices present scenarios that do not accurately describe the nature of equilibrium. For instance, at equilibrium, the forward reaction does not cease; rather, it continues at the same rate as the reverse reaction. Additionally, reactants are not completely consumed at equilibrium; instead, some amount of both reactants and products remains. Lastly, the statement that only products are formed is misleading, as equilibrium involves both reactants and products coexisting in the system.