Chemistry - Halogen Derivative Question with Solution | TestHub

Key Idea: The relative reactivity of alkyl halides towards ${\mathrm{S}}_{\mathrm{N}}2$ reactions is as follows: Primary $>$ Secondary $>$ Tertiary However, if the primary alkyl halide or the nucleophile/base is sterically hindered the nucleophile will have difficulty to getting the back side of the $\alpha$-carbon as a result of this, the elimination product will be predominant. Here ${\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{Br}$ is the least hindered, hence it has the highest relative rate towards ${\mathrm{S}}_{\mathrm{N}}2$ reaction.