Consider the following statements about the classification of halogen compounds.
(A) In allylic halides, the halogen atom is bonded to an sp3-hybridised carbon atom adjacent to a carbon-carbon double bond.
(B) In benzylic halides, the halogen atom is bonded to an sp2-hybridised carbon atom attached to an aromatic ring.
(C) In vinylic halides, the halogen atom is bonded to an sp2-hybridised carbon atom of a carbon-carbon double bond.
(D) In aryl halides, the halogen atom is directly bonded to an sp3-hybridised carbon atom of an aromatic ring.
Which of the statements given above are incorrect? Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → (B) and (D) only
Monohalo compounds are classified by the hybridisation of the carbon atom that carries the halogen. A carbon in a C=C bond or in an aromatic ring is sp2; a carbon with four single bonds is sp3.
(A) In allylic halides, the halogen atom is bonded to an sp3-hybridised carbon atom adjacent to a carbon-carbon double bond. — Correct statement. The halogen is on the allylic carbon, next to the double bond, as in CH2=CH–CH2Br.
(B) In benzylic halides, the halogen atom is bonded to an sp2-hybridised carbon atom attached to an aromatic ring. — Incorrect statement. The halogen is on the side-chain carbon, which has four single bonds and is sp3-hybridised, as in benzyl chloride, C6H5CH2Cl.
(C) In vinylic halides, the halogen atom is bonded to an sp2-hybridised carbon atom of a carbon-carbon double bond. — Correct statement. The halogen is on a carbon of the double bond itself, as in vinyl chloride, CH2=CHCl.
(D) In aryl halides, the halogen atom is directly bonded to an sp3-hybridised carbon atom of an aromatic ring. — Incorrect statement. The ring carbons are sp2-hybridised; chlorobenzene is an example.
NCERT (2026-27 edition):
6.1.2 Compounds Containing sp3 C—X Bond (X= F, Cl, Br, I) – “(b) Allylic halides These are the compounds in which the halogen atom is bonded to an sp3-hybridised carbon atom adjacent to carbon-carbon double bond (C=C) i.e. to an allylic carbon.”
“(c) Benzylic halides These are the compounds in which the halogen atom is bonded to an sp3-hybridised carbon atom attached to an aromatic ring.”
6.1.3 Compounds Containing sp2 C—X Bond – “(a) Vinylic halides These are the compounds in which the halogen atom is bonded to a sp2-hybridised carbon atom of a carbon-carbon double bond (C = C).”
“(b) Aryl halides These are the compounds in which the halogen atom is directly bonded to the sp2-hybridised carbon atom of an aromatic ring.”