<P> In a chemical reaction , chemical equilibrium is the state in which both reactants and products are present in concentrations which have no further tendency to change with time , so that there is no observable change in the properties of the system . Usually , this state results when the forward reaction proceeds at the same rate as the reverse reaction . The reaction rates of the forward and backward reactions are generally not zero , but equal . Thus , there are no net changes in the concentrations of the reactant ( s ) and product ( s ) . Such a state is known as dynamic equilibrium . </P>
when is equilibrium reached in a chemical reaction
when the forward reaction proceeds at the same rate as the reverse reaction