Acidic Oxides

The Acidic Environment‎ > ‎2. Acidic Oxides‎ > ‎

Identify oxides of non-metals which act as acids and describe the conditions under which they act as acids

• Oxides can be classified as acidic, basic, amphoteric or neutral.
  • Acidic oxides: Oxides that display one or both of the following properties:
    • React with bases to form salts.
    • React with water to produce acids.
  • Basic oxides: Oxides that display the following properties:
    • React with acids to produce salts.
    • If soluble, react with water to produce alkaline solutions.
    • Do not react with alkaline solutions.
  • Amphoteric oxides: Oxides that react with both acids and bases.
  • Neutral oxides: Oxides that do not react with either acids or bases.
• Acidic oxides are generally formed by non-metals
• Basic oxides are generally formed by metals.
• Examples of acidic oxides are:
  • Carbon dioxide (CO₂).
  • Diphosphorus pentoxide (P₂O₅).
  • Nitrogen dioxide (NO₂).
• Acidic oxides act as acids when they dissolve in wate.
• For example, carbon dioxide reacts with water to produce carbonic acid:

• This is the reason why indicator paper must be moist in order to detect whether a non-metal oxide gas is acidic.