The product of the following reaction is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → Phenol + C2H5Br
Ethers are cleaved by hydrogen halides. In an alkyl aryl ether such as ethoxybenzene, the O–aryl bond is more stable than the O–alkyl bond, because the oxygen is attached to an sp2 carbon of the ring and the bond has partial double bond character. The ether is protonated, and \( \ce{Br^{-}} \) attacks the ethyl carbon, breaking the O–alkyl bond:
\( \ce{C6H5-O-C2H5 + HBr -> C6H5OH + C2H5Br} \)
The products are phenol and ethyl bromide.
Why the other options are incorrect
Option (2) Bromobenzene + C2H5OH — Incorrect. This needs the O–aryl bond to break; the bond is too strong, and the sp2 carbon of the ring does not undergo nucleophilic attack by \( \ce{Br^{-}} \).
Option (3) 4-Bromoethoxybenzene — Incorrect. Bromination of the ring is an electrophilic substitution that needs bromine (\( \ce{Br2} \)), not HBr.
Option (4) 2-Bromoethoxybenzene — Incorrect. Ring bromination again; HBr cleaves the ether instead of substituting the ring.
NCERT (2026-27 edition):
Chemical Reactions – …
