Amphiprotic Substances

The Acidic Environment‎ > ‎4. Acid/Base Definitions‎ >

Identify amphiprotic substances and construct equations to describe their behaviour in acidic and basic solutions

Amphiprotic substance: A molecule or ion that can behave as either a proton donor or a proton accepter.

• Water is an example of an amphiprotic substance:

• • Can act as an acid (lose a hydrogen ion):

• • Can act as a base (gain a hydrogen ion):

• The hydrogen carbonate ion (HCO₃^–) is an example of an amphiprotic substance:

• • Can act as an acid (lose a hydrogen ion):

• • Can act as a base (gain a hydrogen ion):

• Other examples of amphiprotic substances are the hydrogen sulfate ion (HSO₄^–), the hydrogen phosphate ion (HPO₄^–), and the hydrogen sulfide ion (HS^–).