State and explain the evidence for the delocalisation of electrons in benzene (6 marks)

Benzene does not decolourise bromine water, showing it does not undergo electrophilic addition reactions as the delocalised pi structure is very stable. All of the carbon-carbon bond lengths are the same; the length is intermediate between those expected for carbon-carbon single bonds and carbon-carbon double bonds, showing the electrons are delocalised around the ring.Thermochemically benzene is more stable than the theoretical molecule of cyclohexa-1,3,5-triene due to the added aromatic stability produced by the delocalisation of electrons.