Science Fair Project Encyclopedia
Amphoteric
Amphoteric describes something made of, or acting like, two components.
In chemistry, it indicates a substance that can react with either an acid or base. Examples include amino acids and water. Many metals, such as zinc, tin, aluminium and beryllium, have amphoteric oxides. For example, zinc oxide ZnO reacts differently depending on the pH of the solution:
In acids:
- ZnO + 2H+ → Zn2+ + H2O
In bases:
- ZnO + H2O + 2OH- → [Zn(OH)4]2-
This effect can be used to separate different cations, such as zinc from manganese.
See also:
10-26-2009 08:16:03
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The contents of this article is licensed from www.wikipedia.org under the GNU Free Documentation License. Click here to see the transparent copy and copyright details