Which reaction in each of the following pairs would you expect to be faster?

(d) Thedisplacement byon bromomethane in benzene or in acetonitrile

It is a nucleophilic substitution reaction in which an old bond is broken and a new bond is formed both processes occur simultaneously. Hence, it’s a single-step reaction.

The two reacting species are involved in the rate-determining steps.

Nucleophiles are the negatively charged ions or the neutral species having the lone pair of electrons that are ready for bonding.

If the species is a better leaving group then it reacts faster with the nucleophile

Here, both the solvent are different benzene is non-polar and protic solvent whereas acetonitrile is a polar and aprotic solvent

$S_{N}2$reaction is shown by polar and aprotic solvents.

Acetonitrile is a better leaving group than benzene.

Acetonitrile is show fast reaction than benzene.