In a reversible reaction, chemical equilibrium is attained when the (A) rate of the forward reaction is greater than the rate of the reverse reaction. (B) rate of the reverse reaction is greater than the rate of the forward reaction. (C) concentration of the reactants reaches zero. (D) concentration of the products remains constant.

Answer: (D) concentration of the products remains constant.

Explanation:

The reactions which do not go on completion and in which the reactant forms product and the products goes back to the reactants simultaneously are known as equilibrium reactions.

For a chemical equilibrium reaction, equilibrium state is achieved when the rate of forward reaction becomes equals to rate of the backward reaction. Equilibrium state is the state when reactants and products are present but the concentrations does not change with time.

Thus at chemical equilibrium, the amount of product and reactant remains constant because the rates of the forward and reverse reactions are equal.

A chemical equilibrium is dynamic in nature forward and backward reactions continue for indefinite time and never stops.