Chemistry - Halogen Derivative Question with Solution | TestHub

As with the increase in size${\mathrm{X}}^{-}$bond length increases but bond strength decreases so reactivity increases. As size increases as${\mathrm{F}}^{-}<\mathrm{C}{\mathrm{l}}^{-}<\mathrm{B}{\mathrm{r}}^{-}<{\mathrm{I}}^{-}$.
Hence reactivity order is${\mathrm{C}}_2{\mathrm{H}}_5\mathrm{I}>{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{B}\mathrm{r}>{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{C}\mathrm{l}>{\mathrm{C}}_2{\mathrm{H}}_5\mathrm{F}$