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WHAT ARE THE DIFFERENCES BETWEEN NUCLEOPHILIC SUBSTITUTION UNI MOLECULAR AND BI MOLECULAR REACTIONS(SN1&SN2)?
In organic and inorganic chemistry, nucleophilic substitution is a fundamental class of reactions in which an electron nucleophile selectively bonds with or attacks the positive or partially positive charge of an atom or a group of atoms called the leaving group; the positive or partially positive atom is referred to as an electrophile,

In 1935, Edward D. Hughes and Sir Christopher Ingold studied nucleophilic substitution reactions of alkyl halides and related compounds. They proposed that there were two main mechanisms at work, both of them competing with each other. The two main mechanisms are the SN1 reaction and the SN2 reaction. S stands for chemical substitution, N stands for nucleophilic, and the number represents the kinetic order of the reaction.[4]

In the SN2 reaction, the addition of the nucleophile and the elimination of leaving group take place simultaneously. SN2 occurs where the central carbon atom is easily accessible to the nucleophile. By contrast the SN1 reaction involves two steps. SN1 reactions tend to be important when the central carbon atom of the substrate is surrounded by bulky groups, both because such groups interfere sterically with the SN2 reaction (discussed above) and because a highly substituted carbon forms a stable carbocation.


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