Chemical reaction of PO₄³⁻ ion in water: PO₄³⁻(aq) + H₂O(l) → HPO₄²⁻(aq) +OH⁻(aq). Kb = [HPO₄²⁻] · [OH⁻] / [PO₄³⁻]; base ionization constant. Base ionization constant is the equilibrium constant for the ionization of a base. According
to Bronsted-Lowry theory acid are donor of protons and bases are
acceptors of protons (the hydrogen cation or H⁺). PO₄³⁻ is Bronsted base and it can accept proton and
become conjugate acid HPO₄²⁻.
