Section 06 Products of the chemical or allied 28 Inorganic chemicals; organic or inorganic compounds of precious metals, of rare earth metals, of radioactive elements or isotopes 28 09 Diphosphorus pentaoxide; phosphoric acid and polyphosphoric acids 28 09 20 Hypophosphoric acid 28 09 20 31 Hypophosphoric acid Commodity Code Description 28 09 20 31 00 Hypophosphoric acid