orthophosphoric acid

Etymology

ortho- +‎ phosphoric acid

Noun

orthophosphoric acid (uncountable)

1. (inorganic chemistry) Ordinary phosphoric acid, H₃PO₄
   • 1861, William Odling, A Manual of Chemistry, Descriptive and Theoretical, Part 1‎, page 297:

     Metaphosphoric acid gives a white precipitate with nitrate of silver solution; orthophosphoric acid does not give any, save on the addition of an alkali, and the precipitate then produced is yellow.

   • 1918, Herbert Royl Smith, The Laboratory Study of Chemistry‎, page 124:

     Evaporate 25 cc. of orthophosphoric acid solution to dryness, setting the burner beneath the dish and adjusting the flame so that the tip does not quite touch the dish.

   • 2000, Nicholas P. Cheremisinoff, Practical Guide to Industrial Safety: Methods for Process Safety Professionals‎:

     With the exception of the fertilizer products, most phosphorus compounds are derived from orthophosphoric acid, produced by the oxidation of elemental phosphorus.