Question

28) An E2 reaction of an alkyl halide
a) occurs in two steps
c) will yield an alkene
b) occurs via a carbocation
d) all of the above​

Answer 1

An E2 reaction of an alkyl halide

c) will yield an alkene

E2 reactions are typically seen with secondary and tertiary alkyl halides, but a hindered base is necessary with a primary halide.

The mechanism by which it occurs is a single-step concerted reaction with one transition state.

E2 stands for bimolecular elimination. The reaction involves a one-step mechanism in which carbon-hydrogen and carbon-halogen bonds break to form a double bond (C=C Pi bond). The reaction mechanism involving staggered conformation is more favorable for E2 reactions

alkyl halide will give E2 reaction:

(i) Secondary and tertiary alkyl halides will undergo E2 reactions in the presence of a base like OH-, RO-, R2N−, -E2 reactions are anti-elimination which means that there must be a proton in the beta position of the leaving group.