Chapter 12, Problem 39P

Interpretation Introduction

Interpretation:

The alternative resonance structure for each of the given compounds that all the six membered rings correspond to Kekule forms of benzene is to be written.

Concept introduction:

In the Kekulé structure of notation, all the covalent bonds in the compounds are indicated by the lines and does not include lone pairs or formal charge.

This gives rise two possible structures. Two adjacent carbon atoms are joined by a single bond in one structure while the same two adjacent carbon atoms are joined by a double bond in the other structure.

For benzene there two Kekulé structures, that they have the same connectivity of the atoms, but different arrangement of $\pi$ electrons. This shows that the two Kekulé structures are the resonance forms.