An inorganic example of a triprotic acid is orthophosphoric acid (H3PO4), usually just called phosphoric acid.
ɐn ˌɪnoːɹɡˈænɪk ɛɡzˈæmpəl əvə tɹɪpɹˈɑːɾɪk ˈæsɪd ɪz ˌɔːɹθəfəsfˈɔːɹɪk ˈæsɪd ˈeɪtʃ θɹˈiː pˌiːˈoʊ fˈoːɹ, jˈuːʒuːəli dʒˈʌst kˈɔːld fəsfˈɔːɹɪk ˈæsɪd.