(drawing of the two)
There are three main ways that we can tell the correct structure of benzene consists of a delocalised ring. They are:
- the delocalised structure is more stable that the proposed alkene structure shown by the enthalpy change of formation.
- considering the double bonds, benzene (as a localised structure) would react wth bromine in an addition reaction like any other alkene. however, it undergoes a substitution reaction.
- the bond lengths in benzene are all the same, however kekule's structure suggested that the C-C bonds should be longer than the C=C bonds leading to 3 long and 3 short bonds.