2 Reactions of
Haloarenes
Rationalised 2023-24
182
Chemistry
(ii) Difference in hybridisation of carbon atom in C—X bond: In
haloalkane, the carbon atom attached to halogen is sp3
hybridised while in case of haloarene, the carbon atom attached
to halogen is sp2-hybridised 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 Thus, C—Cl bond length in haloalkane is
177pm while in haloarene is 169 pm Since it is difficult to
break a shorter bond than a longer bond, therefore, haloarenes
are less reactive than haloalkanes towards nucleophilic
substitution reaction