Question

Which of the following will undergo a faster $S_{N}2$?

• A. II
• B. I
• C. Data insufficient. Can’t say.
• D. Both undergo $S_{N}2$ at the same rate

Answer 1

The correct option is B

I

For $S_{N}2$, the ideal substrates are primary or methyl halides (X = Cl, Br, I). Only I is a primary halide and the carbon that undergoes the attack by the nucleophile has to be less hindered. Hence I.