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). // Introduction Chemistry is a large field encompassing many subdisciplines that often overlap with significant portions of other sciences. ... Jump to: navigation, search An acid (often represented by the generic formula AH) is typically a water-soluble, sour-tasting chemical compound. ... The common (Arrhenius) definition of a base is a chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. ...

Examples include amino acids, proteins and water. Many metals, such as lead, zinc, tin, aluminium and beryllium, have amphoteric oxides. For example, zinc oxide ZnO reacts differently depending on the pH of the solution: Jump to: navigation, search In chemistry, an amino acid is any molecule that contains both amino and carboxylic acid functional groups. ... Jump to: navigation, search A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Jump to: navigation, search Water (from the Old English word wæter; c. ... Jump to: navigation, search General Name, Symbol, Number lead, Pb, 82 Chemical series poor metals Group, Period, Block 14, 6, p Appearance bluish white Atomic mass 207. ... Jump to: navigation, search General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ... Jump to: navigation, search General Name, Symbol, Number tin, Sn, 50 Chemical series poor metals Group, Period, Block 14, 5, p Appearance silvery lustrous gray Atomic mass 118. ... Jump to: navigation, search General Name, Symbol, Number aluminium, Al, 13 Chemical series poor metals Group, Period, Block 13, 3, p Appearance silvery Atomic mass 26. ... Jump to: navigation, search General Name, Symbol, Number beryllium, Be, 4 Chemical series alkaline earth metals Group, Period, Block 2, 2, s Appearance white-gray metallic Atomic mass 9. ...

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. A cation is an ion with positive charge. ... Jump to: navigation, search General Name, Symbol, Number manganese, Mn, 25 Chemical series transition metals Group, Period, Block 7, 4, d Appearance silvery metallic Atomic mass 54. ...

See also

• Amphiprotic