Question

In which of the following reactions the rate of the reaction does not depend on the concentration of the nucleophile? A) SN1 and SN2 B) E1 and E2 C) SN1 and E1 D) SN2 and E2 E) SN1 and E2

Answer 1

Answer is option C). SN1 and E1.

The SN1 and E1 reaction and mechanism both are same.

The rate of the reaction depends only on the concentration of substrate not the concentration of nucleophile. thereforre the Sn1 and E1 reactions are called unimolecular reaction.

If changing the concentration of the nucleophill will not affect the rate of the reaction.

The terms S_N1 and E1 mean "substitution, nucleophilic, unimolecular" and "elimination, unimolecular," respectively. These two reaction types are being considered together for two reasons:

1. They often occur simultaneously and competitively with one another, under the same reaction conditions.
2. They each involve the formation of a carbocation as the crucial intermediate in the rate-determining step; these reactions exhibit unimolecular (or "first-order") kinetics, because only one molecule -- the immediate precursor of the carbocation -- is involved in the rate-determining step.