Chemistry - Halogen Derivative Question with Solution | TestHub

The reactivity of alkyl halides towards ${\text{S}}_{\text{N}}2$ reaction depends on the steric hindrance around the carbon atom bearing the halogen.

As steric hindrance increases, the approach of the nucleophile from the backside becomes more difficult, which decreases the rate of the ${\text{S}}_{\text{N}}2$ reaction.

The general order of reactivity for ${\text{S}}_{\text{N}}2$ reactions is: Methyl $>1^{\circ }>2^{\circ }>3^{\circ }$.

Methyl chloride is a methyl halide.

Chloroethane and 1-chlorobutane are primary ($1^{\circ }$) alkyl halides.

Tertiary butyl chloride is a tertiary ($3^{\circ }$) alkyl halide.

Due to maximum steric hindrance from the three bulky methyl groups, tertiary butyl chloride is the least reactive towards ${\text{S}}_{\text{N}}2$ reaction.

Answer: Tertiary Butyl chloride