Question

Among the above given pair, identify one which gives higher heat of hydrogenation?

A. I
B. II
C. Both are equal
D. Cannot be determined

Answer 1

Hint: Heat of hydrogenation of an alkene is the standard enthalpy of reactant hydrogenation of an alkene. Synergist hydrogenation of an alkene is consistently exothermic. Accordingly, the warmth of hydrogenation of alkenes is consistently negative.
Heat of hydrogenation of alkenes is additive, provided that the double bonds are not conjugated.
Heat of hydrogenation of alkenes is a measure of the stability of carbon-carbon double bonds.

Complete step by step answer:
Heat of hydrogenation of an alkene is the standard enthalpy of reactant hydrogenation of an alkene. Synergist hydrogenation of an alkene is consistently exothermic. Accordingly, the warmth of hydrogenation of alkenes is consistently negative.
Heat of hydrogenation of alkenes is a measure of the stability of carbon-carbon double bonds.
Heat of hydrogenation of alkenes is additive, provided that the double bonds are not conjugated.
So, In compound (I), the two fold bonds are not formed.
And In compound (II), the two fold bonds are formed. This results in delocalization of the electron thickness, which gives more noteworthy strength to form diene.
More steady formed dienes have lower warms of hydrogenation than less steady non formed dienes.
Henceforth, compound (I) has higher warmth of hydrogenation than non-formed diene.

Hence, Option (A) is the correct answer.

Note:
Heat of hydrogenation of an alkene is the standard enthalpy of reactant hydrogenation of an alkene. Synergist hydrogenation of an alkene is consistently exothermic. Accordingly, the warmth of hydrogenation of alkenes is consistently negative. Heat of hydrogenation of alkenes is additive, provided that the double bonds are not conjugated.