Chapter 21.5, Problem 33SSC

Interpretation Introduction

Interpretation:

The structure of benzene and its unusual stability needs to explained.

Concept introduction:

Benzene is an aromatic compound with 6 carbon attached to each other in cyclic hexagonal ring. Each carbon is attached to1 hydrogen by single bond and one carbon with double bond on one side and single bond on other side.

Explanation of Solution

The benzene compound looks like a ring of six carbon atoms with three alternate double bonds. The molecular formula of benzene is ${\text{C}}_{\text{6}}{\text{H}}_{\text{6}}$, and is an aromatic compound. The electron orbitals in benzene are present above and below the ring and thus, making it flat and planar molecule with each carbon possessing ${\text{sp}}^{\text{2}}$ hybridization.

Structure of benzene is as follows:

Benzene due to its planar structure and alternate double and single bond in it undergoes resonance (delocalization of electrons) which attributes to its high stability. All the bond lengths are equal and lie in between single and double bond in strength and magnitude unlike to unsaturated cyclic hydrocarbon.

Resonance in benzene occurs as follows:

The delocalization of electron or resonance, it does not undergo addition reactions and inert to most of the reactions that an unsaturated cyclic hydrocarbon undergo, hence is more stable than it.