Chapter 15, Problem 81P

(a)

Interpretation Introduction

Interpretation:

The intermediate (A) formed by the reactants has to be identified.  The mechanism for the formation of intermediate has to be shown.

Concept introduction:

Base abstracts an acidic proton to form a negatively charged species. The negative charged species is called nucleophile. The carbon which is attached to the electronegative atom is called the electrophilic carbon.

In the $S_{N}2$ reaction mechanism, leaving group is displaced by the nucleophile. The increasing order of reactivity of halide is:

${\text{CH}}_3\text{X}>{\text{RCH}}_2\text{X}>{\text{R}}_2\text{CHX}$

(b)

Interpretation Introduction

Interpretation:

The mechanism for the conversion of A to B has to be shown. The compound which formed more rapidly has to be identified.

Concept introduction:

The reaction which takes place between two or more than two atoms which are present in the same molecule are called the intramolecular reactions.