A stable compound has……………………….heat of formation.

Hydrogenation of unsaturated hydrocarbons is an exothermic reaction. Due to hyperconjugation and resonance the stability of unsaturated hydrocarbons increases and the increase in stability is more due to resonance. Compound with same number of pi- bonds and more stability has lower heat of hydrogenation. Heat of formation is defined as the energy evolved when a molecule is formed from its atoms. For isomers the more stable compounds has higher heat of formation. The order of heat of formation of the following molecules is :

Hydrogenation of unsaturated hydrocarbons is an exothermic reaction. Due to hyperconjugation and resonance the stability of unsaturated hydrocarbons increases and the increase in stability is more due to resonance. Compound with same number of pi- bonds and more stability has lower heat of hydrogenation. Heat of formation is defined as the energy evolved when a molecule is formed from its atoms. For isomers the more stable compounds has higher heat of formation. The correct heat of hydrogenation order is : (p) 1,3-Pentadiene (q) 1,3-Butadiene (r) 2,3-Dimethyl-1,3-butadiene (s) Propadiene

A stable compound has ........... Enthalpy of formation.

Enthalpy, Types of reactions, Enthalpy change at standard conditions, Enthalpy of element, Enthalpy of a compound, Heat of formation