Chemical reaction: ClO⁻ + H₂O → HClO + OH⁻.
ClO⁻ is base in this chemical reaction and water is acid. According Brønsted–Lowry acid–base theory base is compound that attracts protons (H⁺) and acid (in this chemical reaction water) gives protons.
Ke = [OH⁻] · [HClO] / [ClO⁻].
[OH⁻] - equilibrium concentration.