Statement I: Ethyl chloride is more reactive than vinyl chloride towards nucleophilic substitution reactions.
Statement II: In vinyl chloride, the chlorine atom is bonded to an sp-hybridised carbon atom.
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → Statement I is correct but Statement II is incorrect.
Vinyl chloride, \( \ce{CH2=CH-Cl} \), is a vinylic halide: the chlorine is bonded to a carbon of the C=C double bond. In ethyl chloride, \( \ce{CH3CH2-Cl} \), it is bonded to an sp3 carbon.
Statement I: Ethyl chloride is more reactive than vinyl chloride towards nucleophilic substitution reactions. — True. The C–Cl bond of vinyl chloride is harder to break, for the same reasons as in aryl halides:
Resonance: the lone pair on chlorine is in conjugation with the π electrons of the C=C bond, so the C–Cl bond gets partial double bond character.
Hybridisation: the sp2 carbon has more s-character, holds the C–Cl electron pair more tightly and gives a shorter, stronger bond than the sp3 carbon of ethyl chloride.
Statement II: In vinyl chloride, the chlorine atom is bonded to an sp-hybridised carbon atom. — False. A carbon of a C=C double bond is sp2-hybridised; sp carbons occur in a C≡C triple bond.
NCERT (2026-27 edition):
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).”
6.7.2 Reactions of Haloarenes – “… C—Cl bond acquires a partial double bond character due to resonance. As a result, the bond cleavage in haloarene is difficult than haloalkane and therefore, they are less reactive towards nucleophilic substitution reaction.”
“The sp2 hybridised carbon with a greater s-character is more electronegative and can hold the electron pair of C—X bond more tightly than sp3-hybridised carbon in haloalkane with less s-chararcter. … Since it is difficult to break a shorter bond than a longer bond, therefore, haloarenes are less reactive than haloalkanes towards nucleophilic substitution reaction.”