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.

AP
Answered by Afia P. Chemistry tutor

25372 Views

See similar Chemistry A Level tutors

Related Chemistry A Level answers

All answers ▸

What is Chatelier's principle?


What is the angle between bonds of a H2O molecule


State the trend in electronegativity for the elements of group 17 and explain why this trend occurs.


Arrange the following elements in order of increasing ionization energy. Give an explanation. a) K, Cs, Na b) F, N, Be


We're here to help

contact us iconContact ustelephone icon+44 (0) 203 773 6020
Facebook logoInstagram logoLinkedIn logo

MyTutor is part of the IXL family of brands:

© 2026 by IXL Learning