Ionization of water

• Water molecules have a slight tendency to undergo reversible ionization to yield a hydrogen ion and hydroxide ion giving the equilibrium,

H₂O ⇌ H⁺ + OH ^– — i)

For generalized reaction,

A+ B ⇌ C + D —ii)

An equilibrium constant can be defined in terms of the concentration of reactant ( A and B) and Product ( C and D) present at equilibrium,

Keq = [C][D] / [A][B]

The equilibrium constant for the reversible ionization of water in equation i) is

Keq = [H⁺ ] [OH^–] / [H₂O]— iii)