Natural gas used as a domestic and industrial fuel consists mainly of which one of the following components?

Introduction / Context:
Natural gas is an important fossil fuel used widely for cooking, heating, power generation, and as a feedstock in the chemical industry. It is a mixture of light hydrocarbons, but one component dominates both in proportion and in significance. General science and geography questions often test whether learners can identify this principal constituent. This question asks specifically which substance is the major component of natural gas used as a fuel.

Given Data / Assumptions:
- The fuel in question is natural gas, taken from underground deposits and used in homes and industries.
- A mixture of different hydrocarbons may be present, but one component forms the bulk of the gas.
- The options include methane, acetone, chlorine, and hexane.
- Standard composition of pipeline quality natural gas is assumed, where methane is predominant.

Concept / Approach:
Natural gas is composed primarily of methane with the chemical formula CH4. Depending on the field, it may also contain small amounts of ethane, propane, butane, carbon dioxide, nitrogen, and other trace gases. However, methane typically accounts for 70 percent to more than 90 percent of the volume. Acetone is an organic solvent, not a main component of natural gas. Chlorine is a reactive halogen element, and hexane is a heavier hydrocarbon liquid at room temperature. Therefore, among the options, methane is the only one that correctly represents the major component of natural gas.

Step-by-Step Solution:
Step 1: Recall from basic science that natural gas is described as a mixture containing mostly methane, along with small amounts of higher hydrocarbons. Step 2: Recognise that methane, CH4, is a light hydrocarbon that is gaseous at normal temperatures and pressures and burns with a clean flame. Step 3: Consider acetone, which is a liquid organic solvent used in nail polish remover and laboratories, not a natural gas component. Step 4: Consider chlorine, which is a yellow green poisonous gas used for disinfection and in industry, not a combustible fuel in natural gas. Step 5: Consider hexane, a heavier hydrocarbon that is liquid at room temperature and is found in petrol fractions, not as the main part of natural gas. Step 6: Conclude that methane is the correct answer as the principal component of natural gas.

Verification / Alternative check:
Energy statistics and chemistry textbooks describe natural gas as consisting mainly of methane. They often define natural gas almost synonymously with methane when explaining combustion and pollution. In diagrams of fractional composition, methane occupies the largest bar, and ethane, propane, and butane are shown only as smaller fractions. Industrial specifications for liquefied natural gas also emphasise high methane content. None of these references describe acetone, chlorine, or hexane as the main constituent. This evidence confirms that methane is the correct choice.

Why Other Options Are Wrong:
Acetone: A volatile solvent used in industries and cosmetics, but not a natural component or main part of natural gas reserves.
Chlorine: A reactive gas used for water treatment and bleach production, not a hydrocarbon fuel component.
Hexane: A liquid hydrocarbon found in petrol and solvents, not the primary constituent of natural gas which is dominated by gaseous methane.

Common Pitfalls:
Learners may overthink the question and look for a more complex hydrocarbon, forgetting that the simplest hydrocarbon, methane, is actually the main natural gas component. Others may confuse natural gas with liquefied petroleum gas, which is richer in propane and butane. Keeping a clear mental distinction between natural gas, LPG, and petrol helps avoid such confusion. Always remember that in most textbook contexts, natural gas is associated with methane as its leading component.

Final Answer:
The major component of natural gas is Methane, a light hydrocarbon with the formula CH4 that forms the bulk of the fuel.