Chapter 8.2, Problem 9P

(a)

Interpretation Introduction

Interpretation:

Which one is a better nucleophiles has to be identified.

Concept introduction:

Nucleophilicity is a measure of how readily a compound is able to attack an electron-deficient atom.

${\text{S}}_{\text{N}}2$Reaction: It is a nucleophilic substitution reaction in which the rate determining step depends on both of the molecules involved.  The bond making and the bond breaking process happens simultaneously in this reaction.  A general ${\text{S}}_{\text{N}}2$ reaction mechanism is given as,

Structure of the substrate plays major role in the reactivity of ${\text{S}}_{\text{N}}2$ reaction.  If the substrate is more substituted then the rate of the reaction will becomes slower.  Since the mechanism of ${\text{S}}_{\text{N}}2$ reaction proceeds through backside attack on the substrate, it depends on steric factor that if more groups attached near the leaving group the reactivity becomes slower.  The ${\text{S}}_{\text{N}}2$ reactivity increases in molecule with better leaving group.

(b)

Interpretation Introduction

Interpretation:

Which one is a strong base has to be identified.