Types of Equilibrium
In chemistry, equilibrium may be classified into two categories, viz., physical equilibrium and chemical equilibrium, depending upon the type of change involved in the system. In physical equilibrium, two or more than two phases of the same substance exist in equilibrium with each other, whereas in chemical equilibrium, different chemical species exist in equilibrium with each other.
As stated above, in physical equilibrium two or more than two phases of the same substance exist in equilibrium with each other. The commonly observed two-phase equilibria along with their main characteristics are described in the following.