Question

Which of the following options have incorrect order of rate in step 2 for different $R-X$?

• A.
• B.
• C.
• D.

Answer 1

Answer: (B), (D)

a) Order is correct as primary halides have more rate for $S_{N}2$.

b) Order is not correct as $Ph-Cl$ has double bond character, so rate of $S_{N}2$ is very less.

c) Order is correct as rate of primary halide is greater than secondary halide for $S_{N}2$ reaction.

d) Order is not correct because tertiary halides are least prone to undergo $S_{N}2$ reaction.