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Friday, June 17, 2011

Chemistry Form 5: Chapter 3 - Redox Reaction

  • Redox reactions are chemical reactions involving oxidation and reduction occurring simultaneously.
  • Oxidising agent is the substance that causes oxidation.
  • Reducing agent is the substance that causes reduction.

Oxidation involves loss of electrons and increase in oxidation number.
Reduction involves gain of electrons and decrease in oxidation number.

Example:


The magnesium's oxidation state has increased from 0 to +2 , it has been oxidised. Magnesium acts as reducing agent. The hydrogen's oxidation state has decreased from +1 to 0 ,  it has been reduced. The hydrogen ion acts as a oxidising agent.

Click on the diagram below to play!




There is no change in oxidation number. Therefore, this is not a redox reaction.

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