Question

Which is the correct order of the following alkyl halides for an SN2 reaction?

• A. ii > i > iii
• B. iii > i > ii
• C. iii > ii > i
• D. ii > iii > i

Hint:

S\textsubscript{N}2 reactions are faster for less hindered alkyl halides — \textbf{primary > secondary > tertiary}.

Answer 1

The Correct Option is B

S\textsubscript{N}2 reactions are favored in less hindered, primary alkyl halides.
- Compound iii is primary and least hindered.
- Compound i is also primary but slightly more hindered.
- Compound ii is secondary and most hindered.
Hence, the reactivity order is: iii > i > ii.