Oxidation & Reduction
- Oxidation and reduction involve the addition or removal of oxygen from a substance
- Oxidation is a reaction in which:
- Oxygen is added to an element or a compound
- Reduction is a reaction in which:
- Oxygen is removed from an element or a compound
- A redox reaction is one where oxidation and reduction are both taking place at the same time
- In the following reaction:
ZnO + C ⟶ Zn + CO
-
- The carbon atom has been oxidised since it has gained oxygen
- The zinc oxide has been reduced since it has lost oxygen
- This is an example of a redox reaction as oxidation and reduction are both taking place
- Carbon is known as a reducing agent as it has reduced another substance (the zinc oxide)
- Zinc oxide is known as an oxidising agent as it has oxidised another substance (the carbon)
Worked example
Magnesium reacts with zinc oxide:
Magnesium + zinc oxide → magnesium oxide + zinc
Explain which substance is reduced and which substance acts as a reducing agent
Answer:
-
- Zinc oxide is reduced because it loses oxygen
- Magnesium acts as the reducing agent as it reduces the zinc oxide
