1-iodopropane The rate of SN2 reactions mainly depends on 1. Steric hindrance of substrate2. Ability of leaving group capacity.Weaker the Carbon-halogen bond most readily reactsThe reactivity order of alkyl halides in SN2 reaction is R – I > R – Br > R – Cl > R – FMost reactive is 1-iodopropaneLeast reactive is 1-fluoropropane