Which of the following compounds contain at least one secondary alcoholic group:
A. 
B. 
C. 
D. 
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A and C only
An alcoholic −OH group is classified by the carbon that carries it: primary (1°) if that carbon is bonded to one other carbon, secondary (2°) if bonded to two other carbons, and tertiary (3°) if bonded to three.
(A) — Correct. The carbon bearing OH also carries H, \( \ce{CH3} \) and \( \ce{CH2CH3} \): butan-2-ol, a secondary alcohol (two carbons attached).
(B) — Incorrect. This is 1-hydroxybutan-2-one, \( \ce{CH3CH2COCH2OH} \); the −OH is on a \( \ce{CH2} \) attached to only one carbon, so it is primary.
(C) — Correct. One −OH is on a terminal \( \ce{CH2} \) (primary), but the other is on a carbon bonded to two carbons (the carbon drawn with H and OH), which is secondary.
(D) — Incorrect. Both −OH groups are on the end carbon, which is bonded to only one other carbon; neither is secondary.
NCERT (2026-27 edition):
Alcohols — Mono, Di, Tri or Polyhydric Alcohols – …
