Chapter 6, Problem 43DSP

Interpretation Introduction

Interpretation:

The reaction which takes place at the fastest rate is to be determined.

Concept Introduction:

In general, ${\text{S}}_{\text{N}}2$ reactions of alkyl halides show the following dependence of rate on structure: $\text{primary > secondary > tertiary}$.

Primary alkyl halides are less crowded at the site of substitution than secondary and tertiary alkyl halides, and thus, react faster in substitution by ${\text{S}}_{\text{N}}2$ mechanism.

Among the alkyl halides, alkyl iodides undergo nucleophilic substitution at the fastest rate while alkyl fluorides at the slowest rate.

The strength of nucleophilicity increases from top to bottom in a group.