Question

State what you understand by nucleophilic substitution of a halogen?

Answer 1

Nucleophilic substitution of a halogen means that the halogen is replaced by a nucleophile in the molecule. The C-X bond in the alkyl halides is polar due to the electronegativity difference between the carbon and the halogen atom and due to this difference the carbon acquires a partial positive charge and the halogen acquires a partial negative charge. This carbon now has become electrophilic in nature due to partial positive charge and can be attacked with the nucleophiles. The incoming nucleophile attacks the carbon and the halogen atom leaves. Hence the halogen atom is substituted by the nucleophile.