Applications
Phosphoric acid is used mainly in fertilizers. It is used as an external standard for phosphorus-31 Nuclear magnetic resonance (NMR); as an electrolyte in phosphoric acid fuel cells and as a catalyst in the hydration of alkenes to produce alcohols, predominantly ethanol. It finds application as a buffer agent in biology and chemistry; as a solution for anodizing and as a cleaner by construction trades to remove mineral deposits, cementitious smears and hard water stains. It is also used as a pH adjuster in cosmetics and skin-care products and a dispersing agent in detergents and leather treatment. It plays an important role in the preparation of albumin derivatives. It is an important starting material used in the preparation of disodium hydrogen phosphate, trisodium phosphate, calcium dihydrogen phosphate and monohydrogen phosphate. It is also used in dentistry and orthodontics as an etching solution as well as a sanitizing agent in dairy, food and brewing industries. It serves as an acidic fruitlike flavoring in food products. It is widely used to remove rust in steel tools or surfaces by converting the rusted ion in to water soluble phosphate compound.

Notes
Incompatible with strong bases and powdered metals.