Major Constituent of natural gas is.

The correct option is Methane.

Step-by-Step Explanation:

1. Understanding Natural Gas: Natural gas is a naturally occurring hydrocarbon gas mixture consisting primarily of alkanes. It is formed deep beneath the Earth's surface through the decomposition of organic matter over millions of years under high pressure and temperature.

2. Composition of Natural Gas: While natural gas contains several different gases, its composition is highly dominated by one specific hydrocarbon:

* Methane (${\mathrm{CH}}_4$): It is the simplest alkane and makes up about 70% to 90% of natural gas by volume.

* Other Hydrocarbons: Ethane ($C_2{H}_6$), Propane ($C_3{H}_8$), and Butane ($C_4{H}_{10}$) are present in much smaller, varying percentages.

* Non-hydrocarbon impurities: Carbon dioxide, nitrogen, hydrogen sulfide, and helium may also be present in trace amounts.

3. Conclusion: Since Methane (${\mathrm{CH}}_4$) constitutes the overwhelming majority of the mixture, it is designated as the major constituent of natural gas. Therefore, the option "Methane" is the correct choice.