Question

Haloalkanes undergo nucleophilic substitutions whereas haloarenes undergo electrophilic substitution

Answer 1

Answer:

Haloalkanes undergo nucleophilic substitution due to high electronegativity of halogen atom .C-X bond in haloalkanes is slightly polar. Carbon has slightly positive charge and halogen has slightly negative charge . Nucleophile which carry negative charge attack on Carbon Nd replace Halogen.

• whereas haloarenes , halogen atom release electron to benzene nucleus i.e electron rich with respect to halogen.
• As a result Electrophile which carry positive charge attack on ortho and para position.

Answer 2

Haloalkanes are more polar than haloarenes. Consequently, the carbon atom carrying the halogen in haloalkane is more electron deficient than haloarenes. As a result, haloalkane undergoes nucleophilic substitution more readily than haloarenes.

In contrast, haloarenes contain a benzene ring. Since the typical reaction of benzene is an electrophilic substitution , therefore haloarenes undergo electrophilic substitution.