Question

Why is benzene extra ordinarily stable though it contains three double bonds?

Answer 1

Benzene is a hybrid of resonating structures given as:

All six carbon atoms in benzene are sp2 hybridized. The two sp2 hybrid orbitals of each carbon atom overlap with the sp2 hybrid orbitals of adjacent carbon atoms to form six sigma bonds in the hexagonal plane. The remaining sp2 hybrid orbital on each carbon atom overlaps with the s-orbital of hydrogen to form six sigma C-H bonds. The remaining unhybridizedp-orbital of carbon atoms has the possibility of forming three π bonds by the lateral overlap of $C_1-C_2,\ C_3-C_4,\ C_5-C_6\ \text {or}\ C_4-C_5,\ C_6-C_1$.

The six $\pi's$ are delocalized and can move freely about the six carbon nuclei. Even after the presence of three double bonds, these delocalized $\pi$-electrons stabilize benzene.