Functional representation of mercaptans (thiols)\nMercaptans are represented structurally as ______ (R and R' denote alkyl groups).

Introduction / Context:
Mercaptans (thiols) are odorous sulphur compounds in petroleum streams, important for odorization (e.g., LPG) and as contaminants requiring sweetening. Knowing their functional formula is foundational to understanding their reactivity and treatment.

Given Data / Assumptions:

• R denotes an alkyl or aryl group; the functional group involves sulphur and hydrogen.

Concept / Approach:
Thiols have the functional group –SH attached to carbon (R–SH). This contrasts with sulfides (R–S–R′) and disulfides (R–S–S–R′). Carboxylic acids (R–COOH) and ethers (R–O–R′) are oxygen-containing, not sulfur-thiol functionalities.

Step-by-Step Solution:

Verification / Alternative check:
Sour gas treating and Merox processes target –SH compounds; reaction schemes depict R–SH oxidation or extraction, confirming the structure.

Why Other Options Are Wrong:

• R–S–R and R–S–R′ are thioethers (sulfides), not thiols.
• R–COOH and R–O–R′ are oxygenated functions.

Common Pitfalls:
Confusing thiols with sulfides due to shared sulfur; odor intensity and reactivity differ markedly.

Final Answer:
R-S-H