AIIMS 2012 Chemistry Question Paper for free online practice with solutions

Aliphatic SN1 reaction is carried out in two steps. In first step carbocation is formed and its formation is based on the stability of carbocation,

In second step, nucleophile is attracted towards carbocation to give final products. Hence, order of SN1 reaction is

The aryl halides e.g.f chlorobenzene are less reactive as compared to alkyl halides towards nucleophilic reagents in either SN2 or SN1 reaction because carbon-halogen bond in the aryl halide is strong (due to its double bond character).