amphoterism

chemistry
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

Print
verifiedCite
While every effort has been made to follow citation style rules, there may be some discrepancies. Please refer to the appropriate style manual or other sources if you have any questions.
Select Citation Style
Feedback
Corrections? Updates? Omissions? Let us know if you have suggestions to improve this article (requires login).
Thank you for your feedback

Our editors will review what you’ve submitted and determine whether to revise the article.

Related Topics:
chemical reactivity

amphoterism, in chemistry, reactivity of a substance with both acids and bases, acting as an acid in the presence of a base and as a base in the presence of an acid. Water is an example of an amphoteric substance. The dissolution of hydrogen chloride (an acid) and ammonia (a base) in water may be represented, respectively, by the following equations:

H2O + HCl ⇌ H3O+ + Cl-

H2O + NH3 ⇌ NH+4 + OH-.

sodium sulfate
More From Britannica
acid–base reaction: Nonaqueous solvents

With hydrogen chloride, water accepts a proton to form a hydronium ion (H3O+), while, with ammonia, water acts as a proton donor and is converted to a hydroxide ion (OH-). Other amphoteric substances include ammonia and the hydroxides of zinc, aluminum, chromium, lead, and tin.