Question

2. Which mechanistic types can undergo a reaction on a primary carbon?

a) E1

b) Sn2

c) Sn1

d) E2

Answer 1

Anwser = option B,D ie Sn2 and E2. Sn2 is most favorable while if the base is strong than E2 can also occur.

Understanding of the concept -

SN1 stands for -substitution, nucleophilic, unimolecular while E1 stands for elimination,unimolecular unimolecular. while E2 for Elimination bimolecular respectively. SN2 and E2 are one step mechanisms while E1 and Sn1 are two step mechanisms.

SN2 in simple terms can be described as - a simple nucleophilic attack of a nucleophile upon electrophilic carbon atom. Which in result causes inversion of complete configuration of the carbon. While in an elimination reaction rather than leaving the group with a nucleophile, the substitute is removed while forming a double bond in the compound.

In case the Carbon is tertiary the nucleophile is weak hence it undergoes E1 or SN1 reaction.

But if the Carbon is primary, like this case then it is SN2 or E2 based on acidic or basic nature. If it is strongly basic then only we consider E2.

So the rate of SN2 reactions is primary > secondary > tertiary while opposite for SN1 and E1