Question

which of these is a condition for dynamic equilibrium?
the reaction must be reversible (can go forward and backward).
the reaction must stop reacting when concentrations stop changing.
the concentration of reactants must equal the concentration of the products.

Explanation:

To determine the condition for dynamic equilibrium:

• For the first option: Dynamic equilibrium occurs in reversible reactions where the forward and reverse reaction rates are equal. So a reversible reaction (can proceed in both directions) is a necessary condition.
• For the second option: In dynamic equilibrium, reactions do not stop; the forward and reverse reactions continue at equal rates. So this statement is incorrect.
• For the third option: At dynamic equilibrium, the concentrations of reactants and products are constant (not necessarily equal). So this statement is incorrect.

Answer:

The reaction must be reversible (can go forward and backward).