Chemistry - Halogen Derivative Question with Solution | TestHub

For a given alkyl group, the reactivity of the halide, $\mathrm{R}-\mathrm{X}$, follows the same order in both the mechanisms-

$\mathrm{R}-\mathrm{I}>\mathrm{R}-\mathrm{Br}>\mathrm{R}-\mathrm{Cl}>\mathrm{R}-\mathrm{F}\mathrm{ }$

It is due to the fact that weaker the base, better it will be the leaving group. Hence, ${\mathrm{I}}^{-}$ is the best leaving group and thus, will have most reactivity.