I)            II)       III) Which of following orders is correct for heat of hydrogenation of these compounds?

As the substituents around the double bond increases,steric crowding around the double bond increases,and hence the addition of hydrogen across the double bond decreasestherefore the energy [heat] released during hydrogenation decreases.Note:  Heat of hydrogenation:-The amount of heat released when one mole of hydrogen added across the double bond is called heat of hydrogenation.AlternativelyH.O.H∞1stability of alkene Stabillity of alkene∞No. of α H- atoms