`Delta_(f)H^(Theta)` of Cyclohexene `(l)` and benzene at `25^(@)C` is `-156` and `+46 kJmol^(-1)`, respectively. `Delta_("hydrogenation")H^(Theta)` of cyclohexene `(l) at 25^(@)C is -119 kJ mol^(-1)`.
Reasonance energy of benzene is found to be `-38x kJ mol^(-1)`. Find the value of `x`.

The standard molar enthalpies of formation of cyclohexane (l) and benzene (l) at 25^(@)C "are" -156 and +49kJ mol^(-1) respectively. The standard enthalpy of hydrogenation of cyclohexene (l) at 25^(@)C is -119kJ mol^(-1) . Use these data to estimate the magnitude of the resonance energy of benzene.