The reaction in which a substance gains oxygen or loses hydrogen is called an oxidation reaction. For example,- c+o2=co2.
cu+o=cuo

Example of Oxidation Reaction:

An example of an oxidation reaction is the reaction between iron and oxygen to form iron(III) oxide, commonly known as rust. The chemical equation for this reaction is:

4Fe + 3O2 → 2Fe2O3

This equation represents the oxidation of iron atoms (Fe) to iron(III) ions (Fe3+) by oxygen (O2) molecules. Let's break down the reaction and understand it in detail:

1. Reactants:
- Iron (Fe): Fe is a metal that is highly susceptible to oxidation. It is the primary reactant in this reaction.
- Oxygen (O2): O2 is a diatomic molecule that is abundant in the atmosphere. It acts as the oxidizing agent in this reaction.

2. Oxidation Process:
- The iron atoms in the reactant (Fe) undergo oxidation. Each iron atom loses three electrons to form iron(III) ions (Fe3+). The electrons lost by the iron atoms are gained by the oxygen atoms.

3. Oxidation States:
- In the reactant side, each iron atom has an oxidation state of 0 since it is in its elemental form. Each oxygen atom has an oxidation state of 0 as well.
- In the product side, each iron atom in iron(III) oxide (Fe2O3) has an oxidation state of +3. Each oxygen atom in Fe2O3 has an oxidation state of -2.

4. Product Formation:
- The reaction yields iron(III) oxide (Fe2O3) as the product. Fe2O3 is commonly known as rust, and it appears as a reddish-brown compound.

5. Balanced Equation:
- The equation is balanced with four iron atoms on each side, three oxygen molecules on the reactant side, and two iron(III) oxide molecules on the product side. This ensures the conservation of mass and charge.

6. Significance:
- This oxidation reaction is commonly observed in the presence of moisture and air, leading to the formation of rust on iron surfaces. Rusting can cause structural damage and deterioration of iron-based materials.

Overall, the oxidation reaction between iron and oxygen to form iron(III) oxide is a classic example of a reaction where a metal is oxidized, and oxygen acts as the oxidizing agent.