Chapter 6.6, Problem 9P

Interpretation Introduction

Interpretation:

It is to be identified that the compound in each of the given pair reacts at a faster rate in an ${\text{S}}_{\text{N}}\text{1}$ reaction.

Concept introduction:

The nucleophilic substitution reaction of methyl and primary alkyl halides proceeds through ${\text{S}}_{\text{N}}2$ mechanism.

The nucleophilic substitution reaction of secondary and tertiary alkyl halide proceeds through ${\text{S}}_{\text{N}}\text{1}$ mechanism.

The ${\text{S}}_{\text{N}}2$ reaction is the bimolecular nucleophilic substitution reaction whose rate determining step involved two reactants both electrophile and nucleophile.

The ${\text{S}}_{\text{N}}\text{1}$ reaction is the unimolecular nucleophilic substitution whose rate determining step involved only one reactant.

The formation of carbocation is the rate determining step in ${\text{S}}_{\text{N}}\text{1}$ mechanism.

The nucleophileattacks on the electrophilic carbon from opposite side of leaving group (i.e. backside attack) in ${\text{S}}_{\text{N}}2$ mechanism.

The nucleophilecan attacks from either face of planar carbocation in ${\text{S}}_{\text{N}}1$ mechanism.

The order of rate of alkyl halide toward substitution by nucleophiles on the basis of better leaving group is $\text{RF}\text{<<}\text{RCl}\text{<}\text{RBr}\text{<}\text{RI}$.