Amphiprotic Definition in Chemistry

Amino acids, such as arginine, are examples of amphiprotic molecules.
Amino acids, such as arginine, are examples of amphiprotic molecules. theasis / Getty Images

Amphiprotic describes a substance that can both accept and donate a proton or H+. An amphiprotic molecule has characteristics of both and acid and a base and can act as either. It is an example of a type of amphoteric molecule.

Amphiprotic Examples

Examples of amphiprotic molecules include amino acids, proteins, and water. Amino acids and proteins have amine and carboxylic acid groups, giving them the ability to be either proton donors or acceptors. Water is self ionizable into H+ and OH-, so it is an excellent example of a molecule that accepts and donates a proton.

Sources

  • Housecroft, C. E.; Sharpe, A. G. (2004). Inorganic Chemistry (2nd ed.). Prentice Hall. pp. 173–4. ISBN 978-0130399137.
  • IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997).