Chapter 9, Problem 9.35P

Interpretation Introduction

Interpretation:

The reactivity difference in the given compounds are should be explained.

Concept Introduction:

${\text{S}}_{\text{N}}\text{1}$ reaction: The displacement of atom or group by nucleophilic is known as nucleophilic substitution.

The rate of the reaction is depends on a single reactant in reaction is known as ${\text{S}}_{\text{N}}1$ unimolecular nucleophilic substitution.

The first step of ${\text{S}}_{\text{N}}1$ is formation of more stable carbocation then addition of nucleophile is the second step.

Frist step is the slow step also rate determining step so the rate of the reaction is depends on the concentration of substrate only.

  $\text{Rate}\text{= k}\left[\text{alkylhalide}\right]$

Nucleophile attacks the both front and back side of carbocation in ${\text{S}}_{\text{N}}1$ reaction therefore result of this racemic product where formed.

Order of the substrate that favored in ${\text{S}}_{\text{N}}1$ reaction is $3°>2°>1°$ .

${\text{S}}_{\text{N}}2$ reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both alkyl halide and the nucleophile present. The bond making and the bond breaking process happens simultaneously in this reaction, which results in the inversion of configuration.

  $\text{Rate}\text{= k}\left[\text{alkylhalide}\right]\text{×}\left[\text{nucleophile}\right]$

Structure of the substrate plays a major role in ${\text{S}}_{\text{N}}2$ reaction. If the substrate is more substituted the rate of the reaction becomes slower. Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate it depends on steric factor of reactant and nucleophile.