Rearrange the compounds of each of the following sets in order of reactivity towards `S_(N)^2` ​displacement :
1-Bromo-3-methylbutane, 2-Bromo-2-methylbutane, 3-Bromo-2-methylbutane

Explanation

Order of reactivity by `S_(N^2)` pathway for nucleophilic substitution in alkyl halides follows the order :
` 1^@ gt 2^@ gt 3^@`
Thus i-bromobutance (a `1^@` alkyi falide) will react faster than 2-bromobutance (a `2^@` ., alkyl halide).
` underset("1-Brainobutanė (a" 1^@ " aikyi halide)") underset(" 2-Bromobutane (a" 2^@" alkyl halide)")(CH_3 - overset(CH_3) overset(|) CH - CH_2 -CH_3)`