Question

Which of the given halides will be most reactive in $S_{N}2$ reaction and $S_{N}1$ reaction, respectively?

• A. $\left(I\right),\left(II\right)$
• B. $\left(II\right),\left(I\right)$
• C. $\left(I\right),\left(III\right)$
• D. $\left(III\right),\left(I\right)$

Answer 1

Answer: (C)

$\left(I\right),\left(III\right)$

$\left(I\right)\Rightarrow 1^o$ allylic halide and less steric hinderance, hence $S_{N}2$.
$\left(II\right)\Rightarrow 3^o$ allylic acid halide, most stable carbonium ion and hence $S_{N}1$.