Why is benzene more stable than the theoretical model cyclohexa-1,3,5-triene?

In cyclohexa-1,3,5-triene the molecule has 3 single bonds and 3 double bonds where all the electrons are localised. As a result the energy needed to hydrogenate cyclohexa-1,3,5-triene is (3x -120kJ/mol) = -360kJ/mol.However, benzene is a planar, aromatic molecule so all of the pz orbitals overlap. The overlap of the pz orbitals form a ring of resonance and allows all 6 pz electrons to be delocalised across the ring. The delocalisation of the pi electrons contributes to the stabalisation energy of benzene. This extra energy from resonance means benzene has a lower hydrogenation energy of -208kJ/mol and is more stable than predicted.

Answered by Afia P. Chemistry tutor

17157 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

Why is methylamine a stronger base than phenylamine?


How do you form a Born-Haber cycle?


What happens to a primary secondary and tertiary alcohol when an excess solution of Potassium Dichromate is added under acidic conditions, state the chemical formula of potassium dichromate?


What is the mechanism for the nucleophilic substitution of a halogenoalkane?


We're here to help

contact us iconContact usWhatsapp logoMessage us on Whatsapptelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

© MyTutorWeb Ltd 2013–2024

Terms & Conditions|Privacy Policy
Cookie Preferences