Haloalkanes And Haloarenes Ques 2
2. In an $S_N 2$ substitution reaction of the type
$R-Br+Cl^{-} \xrightarrow{DMF} R-Cl+Br^{-}$
which one of the following has the highest reactivity rate?
[2008]
(a) $CH_3-CH_2-CH_2 Br$
(b)

(c)

(d) $CH_3 CH_2 Br$
Show Answer
Answer:
Correct Answer: 2.(d)
Solution:
- (d) $S_N 2$ mechanism is followed in case of primary and secondary halides i.e., $S_N 2$ reaction is favoured by small groups on the carbon atom attached to halogens so reactivity order is:

i.e. option (d) is correct.