Benzene ring in phenol is expected to give the characteristic substitution or replacement reactions, i.e., halogenation, nitration, sulphonation, alkylation, etc. In these reactions, the attacking reagent is electrophile. The phenolic group activates the ortho and para positions in the ring due to conjugation. Disubstitution reactions are quite fast as the electron density in the ring has increased considerably. Phenols do not respond to nucleophilic substitution reactions as it is influenced by phenolic group.
Secondary alcohol among the following is:
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → D and E only
An alcohol is secondary (2°) when the carbon carrying the –OH group is bonded to two other carbon atoms; primary when it is bonded to one, tertiary when to three.
(A) (CH3)3C–CH2OH — Not secondary. The –OH carbon (\( \ce{CH2} \)) is bonded to one carbon only, so it is primary (2,2-dimethylpropan-1-ol).
(B) H2C=CH–CH2OH — Not secondary. A primary allylic alcohol (prop-2-en-1-ol); the –OH carbon has one carbon neighbour.
(C) H3C–CH2–CH2OH — Not secondary. Propan-1-ol is primary.
(D) C6H5–CH(OH)–CH3 — Secondary. The –OH carbon is bonded to the ring carbon and to \( \ce{CH3} \): 1-phenylethanol, a secondary benzylic alcohol.
(E) C6H5–CH2–CH(OH)–CH3 — Secondary. The –OH carbon is bonded to \( \ce{CH2} \) and \( \ce{CH3} \): 1-phenylpropan-2-ol.
NCERT (2026-27 edition):
Alcohols— Mono, Di, Tri or Polyhydric Alcohols – “… Monohydric alcohols may be further classified according to the hybridisation of the carbon atom to which the hydroxyl group is attached. (i) Compounds containing Csp3–OH bond: In this class of alcohols, the –OH group is attached to an sp3 hybridised carbon atom of an alkyl group. They are further classified as follows: Primary, secondary and tertiary alcohols: In these three types of alcohols, the –OH group is attached to primary, secondary and tertiary carbon atom, respectively as depicted below:”