The enthalpy of hydrogenation of cyclohexene is -119.5 kJ mol-1. Ilf resonance energy of benzene is -150.4 kJ mol-1, its enthalpy of hydrogenation would be

Dear Student,
Please find below the solution to your problem.

Cyclohexene after hydrogenation would be converted to purely saturated cyclohexane.
As cyclohexene has one pi bond itsenthalpy of hydrogenation is -119.5 kJ mol-1.
In benzene there are 3 pi bonds hence theenthalpy of hydrogenation
= -150.4 kJ –3*(- 119.5 kJ) .
=> 208 kJ

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