Applied chemistry (LPG safety): Ethyl mercaptan is added to otherwise odourless LPG to impart a detectable smell. Identify the chemical family/element that characterizes ethyl mercaptan (ethyl thiol). Choose the correct element.

Given data

• LPG is naturally odourless; a smelly compound (ethyl mercaptan) is added for leak detection.
• Ask: The element/compound class that defines ethyl mercaptan.

Concept/Approach
Ethyl mercaptan is ethyl thiol (C₂H₅SH). Thiols are sulfur-containing analogues of alcohols (–SH group instead of –OH), responsible for the strong characteristic odour.

Reasoning
• The odorant used in LPG is a sulfur compound → answer is sulphur. • Halogens (Cl, F, Br) are not part of ethyl mercaptan's functional group.

Final Answer
Sulphur