List the limitations of Kekulé structure

The Kekulé structure of benzene cannot explain equal bond lengths, stability, or resistance to addition reactions of benzene.

August Kekulé proposed that benzene has a ring of six carbon atoms with alternating single and double bonds. However, experiments show that all carbon–carbon bonds in benzene are equal, which contradicts this model.

The structure also cannot explain benzene’s high stability or its tendency to undergo substitution rather than addition reactions. Spectroscopic studies proved delocalization of π-electrons across the ring, forming resonance structures. Therefore, the modern resonance or molecular orbital model replaced Kekulé’s structure, showing benzene as a planar ring with delocalized electrons.

Limitations summary

• All C–C bonds are equal, not alternating.
• Fails to explain benzene’s extra stability.
• Cannot account for substitution reactions.
• Does not show delocalized π-electrons.