Question

The characteristic smell of LPG (Liquefied Petroleum Gas) is due to the addition of which of the following compounds?

• A. Hydrogen sulphide
• B. Sulphur dioxide
• C. Ethyl mercaptan
• D. Methanethiol

Hint:

Think of "Mercaptan" as the "Scent of Safety." It contains sulphur, which is why it has that characteristic foul smell.

Answer 1

The Correct Option is C

Step 1: Understand the nature of LPG.
LPG (Liquefied Petroleum Gas) is a mixture of propane and butane; in its natural state it is completely odorless and colorless, making gas leaks impossible to detect by the human nose without assistance.
Step 2: Identify the odorant added for safety.
To make leaks detectable, a chemical odorant is deliberately added to LPG before distribution; this compound is Ethyl mercaptan (ethanethiol), which has a strong, distinctive sulfurous smell detectable even in very tiny concentrations.
Step 3: Eliminate incorrect options.
Hydrogen sulphide (H2S) occurs naturally but is not added to LPG; sulphur dioxide (SO2) is an industrial pollutant, not a safety odorant; Methanethiol is similar in class but Ethyl mercaptan is the specific compound added to LPG.
\[ \boxed{\text{Ethyl mercaptan}} \]