PHOSPHORIC ACID
Phosphoric acid is produced industrially by a wet process in which sulfuric acid reacts with apatite (tricalcium phosphate).Ca 5 （PO 4） 3 CI + 5H 2 SO 4 + 10H 2 O → 3H 3 PO 4 + 5 CaSO 4 2H 2 O + HCl
The resulting phosphoric acid solution is about 32-46% H, 3PO4, so the higher concentration of phosphoric acid is concentrated (by water evaporation) to produce industrial grade phosphoric acid.
Pure phosphoric acid is a white crystalline solid with a melting point of 42.35 °C. When the concentration is low, it is a colorless, odorless viscous liquid with a density of 1.885 g/mL. It is non-toxic and non-volatile. The most common concentration of phosphoric acid in water is 85%.