Which of the following is most reactive toward nucleophilic substitution reaction ?

Options

A. `CH_(2) = CH - Cl`
B. `C_(6) H_(5) Cl`
C. `CH_(3) CH = CH Cl`
D. `ClCH_(2) - CH = CH_(2)`

Answer

D

Explanation

In vinyl chlorides and chlorobenzene, the C — Cl bonds have partial double bond character due to resonance. Hence, these do not give nucleophilic substitution reaction easily

On the other hand, allyl chloride or benzyl chloride give nucleophilic substitution very easily as they give stable carbocation
`CH_(2) = CH - CH_(2) Cl overset(-Cl^(-)) (to) CH_(2) underset("Allyl carbocation") (=CH - overset(+)( C)) H_(2)`
`overset(+) ( C) H_(2) - CH = CH_(2) overset(OH^(-))(to) HOCH_(2) - underset("Allyl carbocation") (CH = CH_(2))`