Question

Rank the SN2 reaction rate of the following species.

Rank the S N 2 reaction rate of the following species.

Answer 1

Concepts and reason

In general primary substrate is more reactive in ${\rm{S}}{{\rm{N}}_2}$ reactions. So, determine the reactivity order of the given compounds in ${\rm{S}}{{\rm{N}}_2}$ reaction, on basis of substrate and nature of the leaving group.

Fundamentals

Rate of ${\rm{S}}{{\rm{N}}_2}$ reactions depends on both substrate and nucleophile. That why it is called as nucleophilic bimolecular reaction.

Two factors affect the ${\rm{S}}{{\rm{N}}_2}$ reaction rate are as follows:

Substrate: Primary substrate is faster towards the ${\rm{S}}{{\rm{N}}_2}$ reaction.

Nucleophile: weak bases are best leaving groups. Leaving group ability increases on moving down across the group.

The order of ${\rm{S}}{{\rm{N}}_2}$ reaction rate is as follows:

Ans: