Product name: phosphoric acid food grade Formula: H3PO4 molecular weight: 98.0 CASRN: 7664- ... point:42.35 centigrade. boiling point 213 centigrade,generating pyrophosphoric acid at boilling point. Heating 300 centigrade to become metaphosphoric ... .its acidity is weaker than sulfuric acid, hydrochloric acid and nitric acid, but is stronger than boric acid acetic acid, etc. Can cause skin inflammation ...