Amphoterism
From Open Encyclopedia
- This article is about amphoterism, the chemical property. For the progressive rock band, see Amphoteric (band).
In chemistry, an amphoteric substance is one that can react as either an acid or base (more generally, the word describes something made of, or acting like, two components).
Examples include amino acids, proteins, 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.
Examples
There are many other examples of chemical componds which are also amphoteric, for the most simple example water:
Base:
- H2O + HCl → H3O+ + Cl−
Acid:
- H2O + NH3 → NH4+ + OH−
Aluminium hydroxide is as well:
Base:
- Al(OH)3 + 3HCl → AlCl3 + 3H2O
Acid:
- Al(OH)3 + NaOH → NaAl(OH)4
See also
de:Ampholyt fr:Ampholyte ko:양쪽성 it:Anfotero hu:Amfoter nl:Amfolyt pl:Amfoteryczność fi:Amfolyytti sv:Amfoterisk
