Explained: Why Rusting of Iron Is a Chemical Change

BY Team Aakash Byju's

Rusting: The formation of a new layer of reddish-brown oxide due to the reaction between iron & oxygen is called ‘Rust’.

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A catalyst that is present in the rusting reaction of iron is either a water or air molecule. Iron oxide is the product of the reaction.

The reaction that forms rust is not an instantaneous reaction, it takes place over a large time frame.

In the reaction, the atoms of oxygen bond with atoms of iron thus forming iron oxide.

The rust formed is of  2 types of iron oxides, ferrous oxide (FeO) and ferric oxide Fe2O3.

The chemical reaction of rusting of iron in the presence of water & air molecule is:

Thus the change from iron to rust happens due to a chemical reaction between iron and oxygen.

Did you observe what causes rusting?

Exposure to rain is one of the common reasons for rusting of iron.

The low pH level of the environment surrounding the metal quickens the rusting process.

Exposure to saltwater also increases the speed of rusting by electrochemical reactions in the presence of various salts.

Wondering how to prevent rusting?

‘Galvanization’ is one of the most common processes used to prevent rusting. It involves coating a layer of zinc on a metal.

Hence the rusting of iron, its causes and prevention are all chemical changes.

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