Chapter 9, Problem 9.49P

Interpretation Introduction

Interpretation:

Given substrates are to be ranked in the order of increasing rate of the ${\text{S}}_{\text{N}}\text{2}$ reaction.

Concept introduction:

Strong nucleophiles tend to favor ${\text{S}}_{\text{N}}\text{2}$ reactions. Strong nucleophiles tend to have a total $\text{-1}$ charge. The rate of an ${\text{S}}_{\text{N}}\text{2}$ reaction generally increases as the strength of the base decreases (i.e., as the ${\text{pK}}_a$ of the base’s conjugate acid decreases). The more stable the leaving group is (in the form in which it has left), the better its leaving group ability. Better leaving groups tend to be weaker bases.