The ionic product of water
The dissociation of water
H2O ↔ H+ + OH–
According to law of mass action
K = [H+] [OH–] / [H2O–]
or, K [H2O–] = [H+] [OH–]
or, KW = [H+] [OH–]
KW is the ionic product of water and the va1ue is 1 x 10-14 at 250 temperatures.