amphoterism am·pho·ter·ism (ām'fə-těr'ĭz'əm, ām-fŏt'ə-rĭz'əm)
The quality of exhibiting the characteristics of an acid and a base and having the capacity to react either as an acid or a base.
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:
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