Phosphate Ion, PO4-
Phosphate ion is a reasonably strong base. It hydrolyzes in water to form a basic solution.
HPO42-(aq) + H2O(l) <==> H2PO4-(aq) + OH-(aq) Kb = 1.6 x 10-7
H2PO4-(aq) + H2O(l) <==> H3PO4(aq) + OH-(aq) Kb = 1.3 x 10-12
Phosphates of the alkali metals are soluble. Most other phosphates, such as FePO4, CrPO4, BiPO4, Ca3(PO4)2, and Ag3PO4 are only sparingly soluble. Phosphate ion also forms a bright yellow precipitate with ammonium molybdate:
Phosphate is a very weak oxidizing agent. Since the phosphorus is in its highest oxidation state in phosphate ion, this ion cannot act as a reducing agent.
Go to anion menu