Oxidation and Reduction

In some chemical reactions, oxygen is gained by one chemical and lost by another chemical. We give these processes special names in chemistry.

If a substance gains oxygen, we call it oxidation

If a substance loses oxygen, we call it reduction

If a chemical reaction has oxidation within it, it must also have reduction as well, because one thing must lose the oxygen and another gain it. We give the overall process a special name and call it a REDOX process. It is just a shortened way of saying 'reduction/oxidation' reaction and it sounds much better than OXRED!

e.g.

In this chemical reaction, the CuO has lost its oxygen and turned into Cu. So we would say the Cu in the CuO has been reduced.

The C has gained oxygen and turned into CO₂. So we would say the C has been oxidised.

To further confuse matters, we call the CuO the oxidising agent. This means that it provides the oxygen to oxidise the C.

On the other hand, we call the C the reducing agent, because it reduces (removes the oxygen) from the CuO.

A very special example of a REDOX reaction is the one used to extract the metal iron from its ore, iron ore. This is done on a huge industrial scale because we use so much iron. The large vessel that is used to do this reaction is known as a 'blast furnace'.

The REDOX reaction that takes place in the blast furnace is......

The Fe₂O₃ comes from the iron ore and the CO comes from burning coke (a little bit like coal). You can see in the equation above, the Fe in the Fe₂O₃ is reduced because it loses oxygen. The C in the CO is oxidised because it gains oxygen. Overall, this is a REDOX reaction.

The Fe₂O₃ is the oxidising agent

The CO is the reducing agent