Among the following, which is not the component of coal gas?
A.Methane
B.Hydrogen
C.Oxygen
D.Carbon dioxide

Hint: We have to know that the coal gas is a mixture of gases and it is prepared by heating bituminous coal without the presence of air by a piped distribution system and this process is known as destructive distillation. And this coal is mainly used as fuel. This gas is highly inflammable. And there is some difference between coal gas and natural gas. Because, natural gas is a natural fuel.

Complete answer:
We also remember that methane is a gas and it is the simplest form of hydrocarbon and it is highly flammable. The methane is mainly used as a fuel. And it is a component of coal gas. Hence, option (A) is incorrect.
Hydrogen is an odorless and colorless gas and it is used as fuels. And hydrogen is one of the components of coal gas. Hence, the option (B) is incorrect.
The coals gas is a mixture of gases and it contains the components, methane, hydrogen and carbon dioxide. And it also contains different hydrocarbons, caloric and non- caloric gases like carbon monoxide, nitrogen etc. But, oxygen is not a component of coal gas.
The gases present in coal gas in percentage can be represented as,
\[Hydrogen - 50\% \]
\[methane - 35\% \]
\[carbon\,monoxide - 10\% \]
\[ethylene - 5\% \]
Hence, option (C) is correct.
Carbon dioxide is a component of coal gas. Hence, the option (D) is incorrect.

Note:
Among the given options, oxygen is not a component of coal gas. And it contains only hydrogen, methane, carbon dioxide from the given options. And this coal is prepared by heating it at a temperature of \[400^\circ C\]. This coal is mainly classified into four types and that is, anthracite, bituminous, subbituminous, and lignite.