The Kekule structure of benzene is wrong because:
- Bond length between carbon atoms are all constant and it's somewhere between the length of a c-c bond and a c=c bond (c-c longer than c=c)
- Enthalpy change of hydrogenation is less than expected => the structure is more stable than initially expected
- Does not undergo typical alkene reactions => less reactive
These traits arise due to benzene's structure which is due to multiple p-orbitals overlapping forming a delocalised pi system of electrons (in this case, it contains 6 electrons as it has 6 p-orbitals).
- Low reactivity is due to the spreading out of the electrons which decreases the electron density of the bonds and therefore reduces it's reactivity with electrophiles as they are less strongly attracted.
- The lower enthalpy change of hydrogenation of benzene compared with the kekule structure is due to the greater stability of the delocalised pi system compared to the localised pi bonds (which are more electron dense), the greater t