Chapter 7.15, Problem 33P

Interpretation Introduction

(a)

Interpretation: The mechanism of substitution for the given reaction and the solvent that afford the faster reaction is to be determined.

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 polar protic solvent favors ${\text{S}}_{\text{N}}\text{1}$ reaction whereas polar aprotic solvent favors ${\text{S}}_{\text{N}}\text{2}$ reaction.

Interpretation Introduction

(b)

Interpretation: The mechanism of substitution for the given reaction and the solvent that afford the faster reaction is to be determined.

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 polar protic solvent favors ${\text{S}}_{\text{N}}\text{1}$ reaction whereas polar aprotic solvent favors ${\text{S}}_{\text{N}}\text{2}$ reaction.

Interpretation Introduction

(c)

Interpretation: The mechanism of substitution for the given reaction and the solvent that afford the faster reaction is to be determined.

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 polar protic solvent favors ${\text{S}}_{\text{N}}\text{1}$ reaction whereas polar aprotic solvent favors ${\text{S}}_{\text{N}}\text{2}$ reaction.