Chapter 6, Problem 6.56P

Interpretation Introduction

(a)

Interpretation: The carbon radical which is formed by homolysis of the $\text{C}-{\text{H}}_{\text{a}}$ bond in propylbenzene is to be identified. All reasonable resonance structures for the generated radical is to be drawn.

Concept introduction: The formation of carbocation, carbanion and free radical occur due to the heterolysis or homolysis process. Homolysis is opposite to the heterolysis. It forms radical with an unpaired electron.

Resonance is the delocalisation of $\text{π}$ electrons in conjugated position which leads to the formation of more than one structure. These structures are known as resonance structures.

Interpretation Introduction

(b)

Interpretation: The carbon radical which is formed by homolysis of the $\text{C}-{\text{H}}_{\text{b}}$ bond in propylbenzene is to be identified. All reasonable resonance structures for the generated radical is to be drawn.

Concept introduction: The formation of carbocation, carbanion and free radical occur due to the heterolysis or homolysis process. Homolysis is opposite to the heterolysis. It forms radical with an unpaired electron.

Resonance is the delocalisation of $\text{π}$ electrons in conjugated position which leads to the formation of more than one structure. These structures are known as resonance structures.

Interpretation Introduction

(c)

Interpretation: The weaker $\text{C}-\text{H}$ bond is to be identified.

Concept introduction: The energy which is released or absorbed in the chemical reactions is referred to as bond dissociation energy. The strength of a bond in the reaction is determinedby bond dissociation energy. The chemical reactions in which energy is released from dissociation during the formation of products are known as exothermic reactions. In endothermic reactions, reactants absorb energy to form the desired products. Exothermic and endothermic reactions are opposite to each other. The value of $\text{ΔH°}$ for exothermic and endothermic reactions is positive and negative respectively.