Which will give faster SN2 reaction In $\ce{H2C=CH-Br}$ and $\ce{H3C-CH2-Br}$, which will react faster towards a $\mathrm{S_N2}$ reaction?


According to me, as double bond exhibit −I effect, hence the 1st should do a faster reaction. Am I right, or is there any other reason?
There is no sense of comparing the reaction rate when one of the compound doesn't show SN2 mechanism. And, that compound is $\ce{CH2=CHBr}$, due to the fact that it is a vinyl halide.

$\ce{CH2=CHBr}$ will hinder the approach of nucleophile due to the presence of pi-electron cloud around double bond.

And, therefore the obvious answer is $\ce{CH3-CH2Br}$