amphoteric

Examples of amphoteric in the following topics:

• The Solubility of Amphoteric Metal Hydroxides

  • Amphoteric metal hydroxides behave as bases and acids, dissolving in excess alkali.
  • The oxides and hydroxides of the metals in Group 3 and higher tend to be weakly basic and mostly display an amphoteric nature.
  • An amphoteric substance is one that can act as either an acid or a base.
  • An example of an amphoteric compound that is not amphiprotic is ZnO, which can act as an acid even though it has no protons to donate.
  • An example of an amphoteric and amphiprotic substance is beryllium hydroxide (Be(OH)2):

• Basic and Amphoteric Hydroxides

  • Some metal hydroxides are amphoteric, or capable of acting as either an acid or base.
  • Now we will examine amphoteric hydroxides—that is, hydroxide salts that can act as either an acid or a base, depending on reaction conditions.
  • One of the most common and familiar examples of an amphoteric hydroxide is aluminum hydroxide, Al(OH)3.
  • Metal hydroxides with a highly-charged central metal atom can be amphoteric.
  • In addition to aluminum, metals such as zinc, tin, lead, and beryllium can also form amphoteric oxides or hydroxides.

• Brønsted Acids and Bases

  • Water is amphoteric, which means it can act as either an acid or a base.

• Acid-Base Properties of Water

  • This is an example of autoprotolysis (meaning "self-protonating") and it exemplifies the amphoteric nature of water (ability to act as both an acid and a base).

• Oxides

  • Oxides that react with both acids and bases are amphoteric.
  • Metals tend to form basic oxides, non-metals tend to form acidic oxides, and amphoteric oxides are formed by elements near the boundary between metals and non-metals (metalloids).

• The Brønsted-Lowry Definition of Acids and Bases

  • Note that water is amphoteric; depending on the circumstances, it can act as either an acid or a base, either donating or accepting a proton.

• Chromium

  • Chromium(III) hydroxide (Cr(OH)3) is amphoteric, dissolving in acidic solutions to form [Cr(H2O)6]3+ and in basic solutions to form [Cr(OH)6]3−.

• Oxidation States of Nitrogen

  • If one of the alkyl substituents consists of a long chain, such as C12H25, the resulting amine oxide is an amphoteric surfactant and finds use in shampoos and other mild cleaning agents.

• Synthesis of Amino Acids

  • Since amino acids are amphoteric, resolution could also be achieved by using the basic character of the amine function.

• The Structure and Properties of Water

  • Water can be described as an amphoteric molecule, meaning that it can react as both a Brønsted-Lowry acid or base.