An organic compound with a pleasant smell is likely to have a general formula

Correct answer: C_nH_2n+1COOC_nH_2n+1

Explanation: Compounds with pleasant, fruity odours are typically esters, with general formula R–COO–R′ → here written as C_nH_2n+1COOC_nH_2n+1.

• A. C_nH_2n+1CHO — Aldehydes; often sharp/pungent.
• B. C_nH_2n+1COOH — Carboxylic acids; sour/vinegary smell.
• C. C_nH_2n+1COOC_nH_2n+1 — Correct. Esters (fruity aroma).
• D. C_nH_2n+1COC_nH_2n+1 — Ketones; more solvent-like, not characteristically fruity.