Menthol is an example of which chemical class?

Menthol is an example of which chemical class?

• A. Aldehydes
• B. Esters
• C. Terpenes
• D. Aromatics

Answer: (C)

Terpenes are built from repeating isoprene units, and menthol is a monoterpene formed from two isoprene units that gives a cyclohexane-based framework with an attached hydroxyl group. That combination places menthol squarely in the terpene family, specifically as an oxygenated monoterpene (a terpenoid). It isn’t an aldehyde, since there’s no formyl group (-CHO); it isn’t an ester, since there’s no carbonyl linked to an oxygen in the characteristic ester pattern; and it isn’t aromatic, as there’s no benzene-like ring with the delocalized pi system.