Oxidation and Reduction in Terms of Oxygen/Hydrogen Transfer

Understanding Oxidation and Reduction

  1. Oxidation and reduction can be understood from the aspect of:
    1. Losing or gaining oxygen 
    2. Losing or gaining hydrogen
    3. Transferring of electron
    4. Changing of oxidation number

Oxidation and Reduction in Terms of Oxygen Transfer

  1. Oxidation is the process of gaining oxygen.
  2. Reduction is the process of losing oxygen.
  3. For example, in the extraction of iron from its ore:
    1. Iron(III) oxide loses oxygen. Iron(III) oxide is reduced to iron. This is a reduction process.
    2. Carbon monoxide gains oxygen. Carbon nonoxide is oxidised to become carbon dioxide. This is an oxidising process.

Oxidation and Reduction in Terms of Hydrogen Transfer

  1. Oxidation is the process of losing hydrogen.
  2. Reduction is the process of gaining hydrogen.
  3. For example, ethanol can be oxidised to ethanal:
    1. Ammonia loses hydrogen. Ammonia is oxidised to become nitrogen. This is an oxidation process.
    2. Bromine gains hydrogen. Bromine is reduced to become hydrogen bromide. This is a reduction process.

Example:

Combustion of Magnesium in Air


  • Magnesium is oxidised to become magnesium oxide.


Displacement of copper(II) oxide by Carbon


  • Copper(II) oxide is reduced to become copper metal
  • Carbon is oxidised to become carbon dioxide.


Displacement of lead(II) oxide by Zinc


  • Zinc is oxidised to become zinc oxide.
  • Lead(II) oxide is reduced to become lead metal


Reaction between Magnesium and Steam


  • Water is reduced to become hydrogen gas.
  • Magnesium is oxidised to become magnesium oxide.


Hydrogen Sulphide Reacts with Chlorine


  • Hydrogen sulphide is oxidised to become sulphur.
  • Chlorine is reduced to become hydrogen peroxide.


Copper(II) oxide Reacts with Ammonia


  • Copper(II) oxide is reduced to become copper(II) metal.
  • Ammonia is oxidised to become nitrogen gas.



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