Chapter 6, Problem 4Q

Interpretation Introduction

Interpretation:

The correct decreasing order of reactivity of the ${\text{S}}_{\text{N}}\text{2}$ reaction is to be listed.

Concept introduction:

Nucleophilic substitution reaction is a reaction in which one nucleophile (weak nucleophile) is replaced by a strong nucleophile.

A nucleophile is a molecule or atom with the highest negative charge.

There are two types of nucleophilic substitution reactions: ${\text{S}}_{\text{N}}1$ is a unimolecular reaction and ${\text{S}}_{\text{N}}\text{2}$ is a bimolecular reaction. S_N2 reaction is a second order reaction and the rate depends on concentration of both the reactant and the incoming nucleophile. Primray alkyl halides undergo S_N2 reactions much faster than secondary or tertiary alkyl halides as there is no steric repulsion for the primary alkyl halides which make the attack of the nucleophile more favorable.