Chapter 9, Problem 9.45P

Interpretation Introduction

Interpretation:

The listed nucleophiles, in the order from the slowest ${\text{S}}_{\text{N}}\text{2}$ reaction rate to the fastest in DMSO solvent, are to be ranked.

Concept introduction:

${\text{S}}_{\text{N}}\text{2}$ is a single step bimolecular nucleophilic substitution reaction. The rate of ${\text{S}}_{\text{N}}\text{2}$ reaction depends on both, the substrate as well as the nucleophile. Stronger the nucleophile, greater is the rate of ${\text{S}}_{\text{N}}\text{2}$ reaction. Negatively charged nucleophiles are stronger compared to uncharged ones. Protic solvents solvate the negatively charged nucleophiles and weaken them whereas aprotic solvents do not solvate the nucleophiles. The negative charge is more stable on a larger atom. The positive charge is stable on the less electronegative atom. The stabilization of negative charge by delocalization of $\text{π}$ electrons weakens the nucleophile.