In a `S_(N^(2))` substitution reaction of the type
`R-Br+Cl^(-)overset("DMF")rarrR-Cl+Br^(-)`
Which one of the following has the highest relative rate?

Options

A. `{:(" "CH_(3)),(" |"),(CH_(3)-C-CH_(2)Br),(" |"),(" "CH_(3)):}`
B. `CH_(3)CH_(2)Br`
C. `CH_(3)-CH_(2)-CH_(2)Br`
D. `CH_(3)-underset(CH_(3))underset("| ")(CH)-CH_(2)Br`

Answer

B

Explanation

As primary is more reactive than secondary and tertiary alkyl halides so `CH_(3)CH_(2)Br` has the highest relative rate.