Chapter 24, Problem 103A

Interpretation Introduction

Interpretation:

Stability of benzene over other unsaturated cyclic hydrocarbon is to be explained with light on its structure.

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.

Structure of benzene is as follows:

Answer to Problem 103A

Because of the planar structure and delocalization of electron or resonance, benzene do not undergo addition reactions and is inert to most of the reactions that an unsaturated cyclic hydrocarbon undergo, hence is more stable than it.

Explanation of Solution

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:

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

Conclusion

Because of the planar structure and delocalization of electron or resonance, benzene do not undergo addition reactions and is inert to most of the reactions that an unsaturated cyclic hydrocarbon undergo, hence is more stable than it.