Dynamic equilibrium occurs when

Dynamic equilibrium occurs when

• A. Reactants are completely converted to products with no reactants left.
• B. Molecules of reactants are being converted to products in the same rate as products are being converted to reactants.
• C. The reaction has not reached equilibrium.
• D. The reaction stops when all products are formed.

Answer: (B)

Dynamic equilibrium means the forward and reverse reactions are occurring at the same rate, so the concentrations of both reactants and products stay constant over time. This balance can only exist in a closed system at a given temperature, and even though reactions are still happening in both directions, there is no net change in the amounts present. If all reactants were completely converted to products, there would be nothing left to convert, so the forward rate could not balance the reverse rate—no equilibrium would exist. If the forward and reverse rates aren’t equal, the system is still moving toward equilibrium. If the reaction stopped entirely once products formed, that would be a dead stop, not a dynamic equilibrium where both directions continue to occur.

Dynamic equilibrium means the forward and reverse reactions are occurring at the same rate, so the concentrations of both reactants and products stay constant over time. This balance can only exist in a closed system at a given temperature, and even though reactions are still happening in both directions, there is no net change in the amounts present.

If all reactants were completely converted to products, there would be nothing left to convert, so the forward rate could not balance the reverse rate—no equilibrium would exist. If the forward and reverse rates aren’t equal, the system is still moving toward equilibrium. If the reaction stopped entirely once products formed, that would be a dead stop, not a dynamic equilibrium where both directions continue to occur.