Question

While leakage in L.P.G gas cylinders, gas which gives foul smell is:
(A) Butane
(B) Propane
(C) Methane
(D) Ethyl mercaptan

Answer 1

Hint: This molecular formula of this compound contains a Sulfur atom. It is also used in the manufacture of pharmaceutical products, fungicides, etc. It is a toxic and highly volatile compound.

Complete step by step answer:
- Ethyl mercaptan is used as an additive to odourless gases like butane, propane, etc. to give foul smell which helps to identify the leakages in the L.P.G cylinders.
- Ethyl mercaptan is an organic compound having molecular formula ${{\text{C}}_{\text{2}}}{{\text{H}}_{\text{5}}}{\text{SH}}$.
Butane is a hydrocarbon having the molecular formula ${{\text{C}}_{\text{4}}}{{\text{H}}_{{\text{10}}}}$. Butane is a colourless gas with a faint petroleum-like odour. For transportation it may be stenched. It is shipped as a liquefied gas under its vapour pressure. Contact with the liquid can cause frostbite. It is easily ignited. Its vapours are heavier than air. Any leak can be either liquid or vapour. Under prolonged exposure to fire or intense heat the containers may rupture violently and rocket. It is used as a fuel, an aerosol propellant, in cigarette lighters, and to make other chemicals.
- Propane is one of the components in the L.P.G. It is also an odourless gas. Therefore, it cannot be identified when there is any leakage.
- Methane is the simplest hydrocarbon, consisting of one carbon atom and four hydrogen atoms. Methane is a powerful greenhouse gas. Methane is flammable, and is used as a fuel worldwide. It is a principal component of natural gas.
Therefore option (d) ethyl mercaptan is the correct answer.

Note: Methane, propane and butane are the simple hydrocarbons which is odourless. So, it cannot give any particular smell for any substance.