Describe in brief the characteristics of chemical equilibrium.

The important characteristics of chemical equilibrium are as follows:
(i) At the equilibrium state, all the measurable properties such as concentration, colour, density, partial pressure become constant.
(ii) Chemical equilibrium is dynamic in nature i.e. reaction does not stop but proceeds in both the directions with the same rate.
(iii) Free energy change ∆G = 0.
(iv) Chemical equilibrium can be approached from either direction (either from the reactants or products side).
(v) Equilibrium can be reached only in a closed system.
(vi) The equilibrium state is not affected by the presence of a catalyst as it lowers the same magnitude of activation energy by speeding up both forward and backward reactions to the same extent. However, a catalyst helps to reach the equilibrium state in a shorter period of time.