Chapter 8.4, Problem 11P

Interpretation Introduction

(a)

Interpretation: The change in the rate of an E2 reaction is to be stated when the concentration of alkyl halide is tripled.

Concept introduction: E2 type of reaction follows second order kinetics in which the rate depends on both the reactants. The rate law equation for E2 reaction is expressed as,

$\text{Rate}=\text{k}\left[\text{RX}\right]\left[\text{B:}\right]$

Interpretation Introduction

(b)

Interpretation: The change in the rate of an E2 reaction is to be stated when the concentration of base is halved.

Concept introduction: E2 type of reaction follows second order kinetics in which the rate depends on both the reactants. The rate law equation for E2 reaction is expressed as,

$\text{Rate}=\text{k}\left[\text{RX}\right]\left[\text{B:}\right]$

Interpretation Introduction

(c)

Interpretation: The change in the rate of an E2 reaction is to be stated when the solvent is changed from ${\text{CH}}_{\text{3}}\text{OH}$ to DMSO

Concept introduction: E2 reactions are usually preferred in polar aprotic solvents as the transition state involves charge dispersion which is stabilized by polar aprotic solvents.

Interpretation Introduction

(d)

Interpretation: The change in the rate of an E2 reaction is to be stated when the leaving is changed from ${\text{I}}^{\text{-}}$ to ${\text{Br}}^{\text{-}}$

Concept introduction: A leaving group bigger in size is preferred as it leaves easily and fast while a smaller leaving group leaves with difficulty and slow.

Interpretation Introduction

(e)

Interpretation: The change in the rate of an E2 reaction is to be stated when the base is changed from ${\text{OH}}^{\text{-}}$ to ${\text{H}}_{\text{2}}\text{O}$

Concept introduction: Strong base is more efficient in proton abstraction and hence, it is more preferred in E2 type of reactions.

Interpretation Introduction

(f)

Interpretation: The change in the rate of an E2 reaction is to be stated when the the alkyl halide is changed from ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{Br}$ to ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{CHBr}$.

Concept introduction: The rate of E2 reaction depends on the halide being used. A halide in which carbon attached to the leaving group has more number of alkyl groups is usually preferred.