What are the Possible Mechanisms for Nucleophilic Substitution ?
The replacement of any atom or group of atoms by a nucleophile is known as nucleophilic substitution reaction Nucleophilic substitution reaction depends on nature of nucleophile, nature of leaving group, and nature of solvent.
Nucleophilic substitution unimolecular is a two-step process. First step is the formation of an intermediate that is carbocation. Seconds step is the nucleophilic attack from both side as carbocation so formed is planar in nature as a result of which racemization occurs. The reactivity of SN1 reaction depends on the stability of intermediate formed. Thus, the order of reactivity in SN1 reaction is Tertiary halide > secondary halide > primary halide > methyl halide.
Nucleophilic substitution bimolecular (SN2) reaction is a one step process in which the bond breaking and bond making process takes place simultaneously. Stronger is the nucleophile faster is the reaction.
The better is the leaving group, faster is the reaction.
For a nucleophile to attack the molecule should be less hindered. Thus, the order of reactivity for SN2 in halides will be primary halide > secondary halide > tertiary halide.
Step by step
Solved in 3 steps with 2 images
