Chapter 7, Problem 7.54P

Interpretation Introduction

(a)

Interpretation: The reactant that gives faster ${\text{S}}_{\text{N}}\text{2}$ reaction is to be identified.

Concept introduction: Nucleophilic substitution reaction takes place by two mechanisms, ${\text{S}}_{\text{N}}\text{1}$ and ${\text{S}}_{\text{N}}\text{2}$. In ${\text{S}}_{\text{N}}\text{1}$ mechanism, formation of carbocation takes place by removal of halide and then nucleophile attack on that carbocation. However in ${\text{S}}_{\text{N}}\text{2}$ mechanism, removal of halide and attack of nucleophile takes place simultaneously. The presence of good leaving group increases the rate of both ${\text{S}}_{\text{N}}\text{1}$ and ${\text{S}}_{\text{N}}\text{2}$ reactions.

Interpretation Introduction

(b)

Interpretation: The reactant that gives faster ${\text{S}}_{\text{N}}\text{2}$ reaction is to be identified.

Concept introduction: Nucleophilic substitution reaction takes place by two mechanisms, ${\text{S}}_{\text{N}}\text{1}$ and ${\text{S}}_{\text{N}}\text{2}$. In ${\text{S}}_{\text{N}}\text{1}$ mechanism, formation of carbocation takes place by removal of halide and then nucleophile attack on that carbocation. However in ${\text{S}}_{\text{N}}\text{2}$ mechanism, removal of halide and attack of nucleophile takes place simultaneously. The presence of good leaving group increases the rate of both ${\text{S}}_{\text{N}}\text{1}$ and ${\text{S}}_{\text{N}}\text{2}$ reactions.

Interpretation Introduction

(c)

Interpretation: The solvent that gives faster ${\text{S}}_{\text{N}}\text{2}$ reaction is to be identified.

Concept introduction: Nucleophilic substitution reaction takes place by two mechanisms, ${\text{S}}_{\text{N}}\text{1}$ and ${\text{S}}_{\text{N}}\text{2}$. In ${\text{S}}_{\text{N}}\text{1}$ mechanism, formation of carbocation takes place by removal of halide and then nucleophile attack on that carbocation. However in ${\text{S}}_{\text{N}}\text{2}$ mechanism, removal of halide and attack of nucleophile takes place simultaneously. The presence of good leaving group increases the rate of both ${\text{S}}_{\text{N}}\text{1}$ and ${\text{S}}_{\text{N}}\text{2}$ reactions.