Phosphoric Acid is a mineral (inorganic) and weak acid having the chemical formula H3PO4.  The most common source of phosphoric acid is an 85% aqueous solution; such solutions are colourless, odourless, and non-volatile. The 85% solution is a syrupy liquid, but still pourable. Although phosphoric acid does not meet the strict definition of a strong acid, the 85% solution is acidic enough to be corrosive.

Phosphoric acid has been used as an acid solution for pH adjustment of the fermentation broth in a protocol for the acetone-butanol-ethanol (ABE) fermentation of sugars in a bioreactor. Industrially, phosphoric acid may be used in fertilizers, detergents, pharmaceuticals, water treatment, food additive and cleaning products.