Pure water is a weak electrolyte. Water disassociates  into hydrogen [H⁺] and hydroxide [OH^-] ions but exist in equilibrium. Salt hydrolysis is defined as a reaction in which the cation or anion or both of a salt react with water to produce acidity or alkalinity.

Salts are strong electrolytes. Salts dissolved in water and dissociate completely into ions. In some salts, cations react with water to produce H⁺ ions in acidic condition.

M⁺ +   H₂O    MOH    +  H⁺

                     Weak base

In other salts, anions react with water to produce OH^- ions and becomes basic.

  A^- +   H₂O     HA   +  OH^-

                      Weak acid