The equilibrium constant of a chemical reaction is defined as the value of the reaction quotient when the reaction has reached a state of equilibrium. Equilibrium constant value is independent of the analytical concentrations of the reactant and product species in a mixture, but depends on temperature and ionic strength.

Equilibrium constant has two broad applications in the form of -

1. Prediction of the quantities of products formed, and hence the amount of reactant left,

2. To understamd the types of products that would form in a chemical reaction.