Explain as to why haloarenes are much less reactive than' haloalkanes towards nucleophilic substitution reactions?

Explain as to why haloarenes are much less reactive than' haloalkanes

1.	Explain as to why haloarenes are much less reactive than' haloalkanes towards nucleophilic substitution reactions?
Answer» Solution :Haloarenes are much LESS reactive than haloalkanes towards nucleophilic substitution reactions due to the following reasons: (i) RESONANCE effect: In haloarenes the electron pair on the halogen atom is in conjugation with the T-electrons of the ring and the following resonating structures are possible. C-CI bond ACQUIRES a partial double bornd character due to resonance. As a result. the bond cleavage in haloarenes is difficult than in case of haloalkanesand therefore they are less reactive towards nucleophilic substitution reactions. (ii) The C-Cl bond length in haloalkanes is 177 pm while in haloarenes it is 169 pm. Since it is difficult to break shorter bond than a longer bond. Therefore, haloarenes are less reactive than haloalkanes towards nucleophilic substitutión reactions.