Phosphoric acid, kuma aka sani da orthophosphoric acid, wani inorganic acid ne da aka saba amfani dashi a masana'antu daban-daban. Yana da matsakaicin matsakaicin acidity, tsarin sinadarai shine H3PO4, kuma nauyin kwayoyin sa shine 97.995. Ba kamar wasu acid masu canzawa ba, phosphoric acid yana da ƙarfi kuma baya rushewa cikin sauƙi, yana mai da shi ingantaccen zaɓi don aikace-aikace iri-iri. Yayin da phosphoric acid bai da ƙarfi kamar hydrochloric, sulfuric, ko nitric acid, ya fi acetic da boric acid ƙarfi. Bugu da ƙari kuma, wannan acid yana da babban kaddarorin acid kuma yana aiki a matsayin mai rauni na tribasic acid. Ya kamata a lura cewa phosphoric acid shine hygroscopic kuma yana ɗaukar danshi daga iska. Bugu da ƙari, yana da yuwuwar canzawa zuwa pyrophosphoric acid lokacin zafi, kuma asarar ruwa na gaba zai iya canza shi zuwa acid metaphosphoric.