The correct option is (c).
Explanation
Combustion is a fundamental chemical process in which a substance reacts rapidly with oxygen to generate heat. It is classified as an exothermic reaction and may or may not be accompanied by light.
- Statement 1 is Correct: Combustion is a chemical process because it involves a chemical reaction between a fuel and an oxidant (usually atmospheric oxygen), resulting in the formation of new chemical substances (typically oxides) and the release of energy.
- Statement 2 is Incorrect: A flame is produced only when a substance vaporizes during burning. Substances like wax or kerosene vaporize and thus burn with a flame. However, substances like charcoal do not vaporize; they burn with a red glow but do not produce a flame. Therefore, a flame is not an inevitable result of all combustion processes.
- Statement 3 is Correct: The process of combustion strictly requires a combustible substance (fuel) to act as the reactant that undergoes oxidation. Without a combustible material, the reaction cannot initiate.
Key Takeaway: While all combustion involves the generation of heat through chemical oxidation, the production of a flame is conditional and occurs only if the combustible substance vaporizes during the process.