What is the difference between Sn1 and Sn2 reactions ?
1. For SN1 reactions, the step determining the rate is unimolecular, whereas for a SN2 reaction, it is bimolecular.
2. SN1 is a two-step mechanism, whereas SN2 is only a one-step process.
3. During SN1 reactions, the carbocation will form as an intermediate, whereas, during SN2 reactions, it is not formed.
4. In SN2 reactions, one can draw the intermediate structure of where the carbon has a partial bond with the incoming nucleophile and the leaving group, whereas this is not possible in SN1 pathway reactions.