What are redox reactions?

The reactions in which both oxidation and reduction takes place simultaneously are known as redox reactions.

Example: Reaction of ferric oxide with carbon monoxide to form iron and carbon dioxide as shown below:-

In the above reaction ferric oxide (Fe₂O₃) is reduced into iron (Fe) by losing the oxygen atoms attached to it and carbon monoxide (CO) is oxidized into carbon dioxide (CO₂) by gaining the oxygen atoms.