Phosphoric acid (H₃PO₄) is a common inorganic acid, belonging to the medium-strong acid, with the characteristics of a tribasic acid, which can gradually release three protons to form different protonated forms. ‌

Physical properties:

Phosphoric acid is a colorless and transparent solid at room temperature, with a melting point of 42°C, and becomes a viscous liquid after heating. In industry, it often exists in the form of an 85% aqueous solution, which is colorless, odorless, and non-volatile. ‌

Chemical properties:

As a tribasic acid, phosphoric acid ionizes in three steps to release hydrogen ions, forming three ions: H₂PO₄⁻, HPO₄²⁻, and PO₄³⁻. It has the general properties of an acid, but its oxidizing property is weak. It is easy to dehydrate when heated to form polymerization products such as pyrophosphate and metaphosphoric acid. ‌

Main uses:

It is widely used in agriculture (production of fertilizers), food (additives), medicine (drug raw materials), industry (electroplating, polishing, fireproof materials), laboratory reagents and other fields. Phosphate is an essential nutrient element for organisms.