Orthophosphoric acid, H3P04, a tribasic acid, is obtained by boiling a solution of the pentoxide in water; by oxidizing, red phosphorus with nitric acid, or yellow phosphorus under the surface of water by bromine or iodine; and also by decomposing a mineral phosphate with sulphuric acid.
Numerous hydrides are known; heated with red phosphorus and hydriodic acid the hydrocarbon yields mixtures of hydrides of composition C10H10 to C10H20.
On oxidation it gives triphenylcarbinol, (C 6 H 5) 3 C OH, and reduction with hydriodic acid and red phosphorus gives benzene and toluene.
It decomposes when heated, hydrogen and red phosphorus being formed.
It slowly reacts with cold water to form phosphorous acid; but with hot water it is energetically decomposed, giving much red phosphorus or the suboxide being formed with an explosive evolution of spontaneously inflammable phosphoretted hydrogen; phosphoric acid is also formed.