Acids & Bases
What You’ll Learn
Diprotic acids are acids that can donate two hydrogen ions (protons) per molecule in successive ionization steps. Polyprotic acids are acids that can donate more than two hydrogen ions per molecule through multiple ionization steps. A common example of a diprotic acid is sulfuric acid (H2SO4), which ionizes in two steps by losing two protons. Phosphoric acid (H3PO4) is an example of a triprotic (polyprotic) acid that can lose three protons in successive ionization steps.