Justify and arrange the following compounds namely
in increasing order of reactivity towards the asked displacement namely :
(a)
(b)
a) C6H5CH2Br < C6H5CH(Br)CH3 < C6H5C(Br)(CH3)2 due to increasing stability of carbocation
b) C6H5C(Br)(CH3)2 < C6H5CH(Br)CH3 < C6H5CH2Br due to decreasing steric hindrance.