Match List-I with List-II.
| List-I (Alcohol) | List-II (Class of alcohol) |
|---|---|
| (A) \( \ce{CH2=CH-CH2OH} \) | (I) Secondary alcohol |
| (B) \( \ce{C6H5CH2OH} \) | (II) Allylic alcohol |
| (C) \( \ce{(CH3)3C-OH} \) | (III) Tertiary alcohol |
| (D) \( \ce{CH3CH(OH)CH2CH3} \) | (IV) Benzylic alcohol |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → A-II, B-IV, C-III, D-I
Monohydric alcohols are classified by the carbon atom that carries the –OH group: whether it is primary, secondary or tertiary, and whether it lies next to a carbon-carbon double bond (allylic) or next to an aromatic ring (benzylic).
(A) \( \ce{CH2=CH-CH2OH} \) (prop-2-en-1-ol) — This matches (II) Allylic alcohol. The –OH is on an sp3 carbon that is next to the C=C double bond.
(B) \( \ce{C6H5CH2OH} \) (phenylmethanol) — This matches (IV) Benzylic alcohol. The –OH is on an sp3 carbon next to the benzene ring.
(C) \( \ce{(CH3)3C-OH} \) (2-methylpropan-2-ol) — This matches (III) Tertiary alcohol. The carbon carrying –OH is bonded to three other carbon atoms.
(D) \( \ce{CH3CH(OH)CH2CH3} \) (butan-2-ol) — This matches (I) Secondary alcohol. The carbon carrying –OH is bonded to two other carbon atoms.
Compounds (A) and (B) are also primary alcohols, because allylic and benzylic alcohols may be primary, secondary or tertiary; List-II offers only their allylic and benzylic class.
NCERT (2026-27 edition):
7.1.1 Alcohols— Mono, Di, Tri or Polyhydric alcohols – “…Primary, secondary and tertiary alcohols: In these three types of alcohols, the –OH group is attached to primary, secondary and tertiary carbon atom, respectively …”
“Allylic alcohols: In these alcohols, the —OH group is attached to a sp3 hybridised carbon adjacent to the carbon-carbon double bond, that is to an allylic carbon.”
“Benzylic alcohols: In these alcohols, the —OH group is attached to a sp3—hybridised carbon atom next to an aromatic ring.”
“Allylic and benzylic alcohols may be primary, secondary or tertiary.”