The principal constituent of natural gas is

Analysis

The question asks for the primary chemical component found in natural gas. Natural gas is a fossil fuel energy source that consists mostly of simple hydrocarbons.

Concept

Natural gas is primarily composed of alkanes, which are saturated hydrocarbons. While natural gas can contain small amounts of ethane, propane, and butane, the vast majority (often 70% to 90%) of its composition is the simplest alkane, which has the chemical formula $CH_4$.

Solution

1. Identify the components: Natural gas is a mixture of gaseous hydrocarbons.
2. Evaluate the options: • Methane ($CH_4$): This is the simplest hydrocarbon and the most abundant component in natural gas deposits. • Ethane ($C_2H_6$): Present in smaller quantities. • Propane ($C_3H_8$) and Butane ($C_4H_{10}$): These are often separated from natural gas to be sold as Liquefied Petroleum Gas (LPG) for cooking and heating.
3. Conclusion: Since methane makes up the largest percentage of natural gas, it is considered its principal constituent.

Correct Answer

The correct option is A.

Exam Tip

To remember this easily, think of the acronym "MEP-B" for the first four alkanes (Methane, Ethane, Propane, Butane). Always remember that Methane is the "king" of natural gas, while Butane/Propane are the main components of the gas cylinders we use in our kitchens (LPG).