Chemistry - Halogen Derivative Question with Solution | TestHub

The $S_{N}1$ mechanism involves the formation of a carbocation intermediate in the rate-determining step.

The reactivity of alkyl halides towards $S_{N}1$ substitution depends on the stability of the carbocation formed. The order of stability of carbocations is $3^{\circ }>2^{\circ }>1^{\circ }>\text{methyl}$.

Among the given options, $({\text{CH}}_3{)}_3\text{C-Br}$ is a tertiary alkyl halide, which forms a highly stable tertiary carbocation, $({\text{CH}}_3{)}_3{\text{C}}^{+}$.

Therefore, it preferably undergoes alkaline hydrolysis by the $S_{N}1$ mechanism. The other options are methyl and primary alkyl halides, which preferably undergo the $S_{N}2$ mechanism.

Answer: $({\text{CH}}_3{)}_3\text{C-Br}$