**Exothermic Reaction:**
Combustion is an exothermic reaction. In an exothermic reaction, energy is released in the form of heat or light. When a substance undergoes combustion, it reacts with oxygen to produce heat and light. The energy released during combustion is usually in the form of heat, which can be used to do work or to raise the temperature of the surroundings.

**Explanation:**
- Combustion is a chemical reaction in which a substance reacts with oxygen to produce heat and light.
- The reaction typically involves the burning of a fuel, such as wood, coal, or gasoline.
- During combustion, the fuel molecules break apart and combine with oxygen molecules from the air.
- This reaction releases energy in the form of heat and light.
- The heat and light produced during combustion are the result of the exothermic nature of the reaction.
- Exothermic reactions release energy because the products of the reaction have lower energy than the reactants.
- In the case of combustion, the reactants (fuel and oxygen) have higher energy than the products (carbon dioxide and water vapor).
- The difference in energy is released as heat and light.

**Examples of Combustion:**
- Burning of wood: When wood is burned, it reacts with oxygen from the air to produce carbon dioxide and water vapor, releasing heat and light.
- Burning of gasoline in a car engine: Gasoline reacts with oxygen in the engine to produce carbon dioxide and water vapor, releasing energy that powers the car.
- Burning of natural gas in a stove: Natural gas reacts with oxygen to produce carbon dioxide and water vapor, releasing heat that cooks food.

**Conclusion:**
In conclusion, combustion is an exothermic reaction because it releases energy in the form of heat and light. This energy is produced as a result of the chemical reaction between a fuel and oxygen, which leads to the formation of carbon dioxide and water vapor.

This is why because exothermic reactions are those in which heat is given out and as it's name giving us idea exo means out or exit and thermic meaning thermal energy which is heat. as we know if we burn wood it is also combustion and we fell hot when we go near the burning wood that means heat is giving out
Hope it will help you 🙂👍☺️