Question

Which gas is an essential constituent of almost all fuel gases?
(A) $C{{O}_{2}}$
(B) ${{N}_{2}}$
(C) $CO$
(D) ${{H}_{2}}O$

Answer 1

The fuel is composed of carbon and hydrogen which on combustion with the air, produce various other substances. The combustion process may be complete (gives water and carbon dioxide) or maybe incomplete (gives carbon monoxide) producing substances, which may further act as fuel, combining with hydrocarbons and hydrogen.

Complete step by step solution:
Fuel is present in all three states. In the gaseous form, it is known as the fuel gas. They are present both naturally or can be manufactured from solid or liquid fuels.
The gaseous fuels present naturally are natural gas and the liquified petroleum gas. Whereas the gas fuels generally produced through other materials by artificial processes are the coal gas, water gas, synthesis gas and the producer gas.
These gas fuels are composed of carbon monoxide ($CO$), methane (or other hydrocarbons) and hydrogen or their mixtures as its constituent.

Therefore, making the option (C)-$CO$ gas as an essential constituent of almost all fuel gases.

Additional information:
Though the transportation and distribution of the fuel gases are done readily by the pipelines. Precautions are taken to avoid its leakage by adding odorants like methyl mercaptan which has a distinct smell and so it is easily detected.
These fuel gases are pollution-free as they burn completely, that is smokeless and ashless.

Note: The components of the fuel gases make it to have high calorific value and the lowest ignition temperature. Thus, on burning it produces high efficiency and high-temperature flame which can be controlled and adjusted easily.