The enthalpy of hydrogenation of cyclohexene is -119.5 kJ mol^-1. If resonance energy of benzene is -150.4 kJ mol^-1, calculate its enthalpy of hydrogenation in kJ.

The resonance energy provides extra stability to the benzene molecules so it has to be overcome, for hydrogenation to take place, so  $\mathrm{\Delta F}=-358.5-(-150.4)=-208.1\mathrm{kJ}$