Substitution Reactions of Haloalkanes

Substitution reactions are those in which an atom or a group of atoms from the reactant molecule is displaced by another atom or a group of atoms. For example, on treating chloroethane with sodium hydroxide, the chlorine atom of chloroethane is substituted by the hydroxyl group and ethanol is formed as the reaction product.

Nucleophilic Substitution Reactions

The hydroxide ion (nucleophile) displaces the chlorine atom from C2H5Cl as chloride ion (another nucleophile). Such reactions which are initiated by the attack of a nucleophile are known as nucleophilic reactions. In haloalkanes, the carbon atom carrying the halogen atom is electron deficient due to –I effect of halogen atom. This electron deficient carbon atom is susceptible to attack by a nucleophile.