1. (of an acid) capable of donating two protons or hydrogen ions in a chemical reaction
Usage: chemistry; technical

Examples

• Sulfuric acid is a diprotic acid because it can donate two protons.
• In the lab, we studied the titration of a diprotic acid with a strong base.
• Carbonic acid is diprotic and can form both bicarbonate and carbonate ions.
• The diprotic nature of oxalic acid makes it useful in analytical chemistry.
• Students learned that diprotic acids have two ionization constants, Ka1 and Ka2.