Dear student, There are two types of chemical equilibrium.
Homogeneous equilibrium: An equilibrium reaction in which all the reactants and products are in the same phase is called a homogeneous reactions. Ex. N2(g) + 3H2(g) ⇌ 2NH3(g)
Heterogeneous equilibrium: An equilibrium reaction in which various reactants and products are in different phase is called a homogeneous reaction. Ex. CaCO3(s) ⇌ CaO(s) + CO2(g)