Haloalkanes undergo nucleophilic substitutions whereas haloarenes undergo electrophilic substitutions. Explain.
Answer : Haloalkanes undergo nucleophilic substitution reactions more readily because haloalkanes are more polar than haloarenes. The reason being that in haloalkanes, the carbon atom attached to the halogen atom is sp3 hybridized whereas in haloarenes, it is sp2 hybridized. Since an sp3 hybridized carbon is less electronegative than an sp2 hybridized carbon, the electronegativity difference in the C−X bond of haloalkanes is greater, making them more polar.
On the other hand, haloarenes contain a benzene ring. Since typical reactions of benzene are electrophilic substitution reactions, compounds containing benzene ring such as haloarenes also undergo electrophilic substitution reactions.
That is why haloalkanes undergo nucleophilic substitution reactions whereas haloarenes undergo electrophilic substitution reactions.