The order of reactivities of the following alkyl halides for a ${{\rm{S}}_{\rm{N}}}2$ reaction is :

$R{\rm{I}}\; > \;R{\rm{Br\;}} > \;R{\rm{Cl}}\; > \;R{\rm{F}}$

$R{\rm{F}}\; > \;R{\rm{Cl\;}} > \;R{\rm{Br}}\; > \;R{\rm{I}}$

$R{\rm{F}}\; > \;R{\rm{Br\;}} > \;R{\rm{Cl}}\; > \;R{\rm{I}}$

$R{\rm{Cl}}\; > \;R{\rm{Br\;}} > \;R{\rm{F}}\; > \;R{\rm{I}}$

NEET UG CHEMISTRY MCQ: HALOALKANES AND HALO ARENES

1 Easy

1 of 1

Understanding +4 | -1

The order of reactivities of the following alkyl halides for a

{\mathrm{S}_\mathrm{N}}2

reaction is :

View answer and explanation

Correct option: D

R\mathrm{I}\; > \;R\mathrm{Br\;} > \;R\mathrm{Cl}\; > \;R\mathrm{F}

Option D (

R\mathrm{I}\; > \;R\mathrm{Br\;} > \;R\mathrm{Cl}\; > \;R\mathrm{F}

) is correct because the reactivity of alkyl halides in

S_N2

reactions increases as the size of the halogen increases, due to the weakening of the C-X bond.