PCl3 + 2H2O + H3PO4 3HCl + H4P2O6
or
PCl3 + 2H2O + H3PO4 3HCl + [H3(HP2O6)]
Phosphorus(III) chloride react with water and phosphoric acid to produce hydrogen chloride and isogipophosphoric acid. This reaction takes place at a temperature near 50°C.