Predict the product of the following reaction:
Benzene `+H_2to`?
Strategy: Adding 1 mol `H_2` to benzene is endothermic while adding 1 mol `H_2` to chlohexadiene is exathermic Thus, when benzene is reduced to diene, the cyclohexadiene is reduced all the way to cyclohexane before more benzene reacts.

Explanation

According to the rate of hydrogenation and the number of moles of hydrogen used (3 mol `H_2` for every 1 mol of cyclohexane from benzene), for every one mole of benzene, one third of a mole of cyclohexane would be isolated and two third of a mole of benzene would be recovered.