Question

Heat of hydrogenation of cyclohexane is -119KJ and heat of hydrogenation of benzene is 206KJ/mole. Find the resonance energy of benzene.

Answer 1

Enthalpy of hydrogentaion of benzene is negative 206 kj/mol
Enthalpy of hydrogentaion of cyclohexene = -119 kJ/mol
Therefore,
calculated enthalpy of hydrogenation of benzene=3(-119 ) = -357 kJ/mol

​​​​​enthalpy of hydrogenation of benzene = -206.kJ/mol

Resonance energy = enthalpy of hydrogentaion of benzene - calculated enthalpy of hydrogenation of benzene.
=-206 - (-357) = - 169 kJ/mol