The order of heat of hydrogenation in following compound is:
The order of heat of hydrogenation in following compound is:
The correct option is B III < IV < II < I
The heat of hydrogenation is inversely proportional to the stability of a compound, hence more stable is the compound, less is its heat of hydrogenation.
There is a phenomenon called Hyperconjugation, which determines stability. According to this factor, if there are more number of Alpha hydrogens, (hydrogens attached to the carbon adjacent to the carbon directly attached with double bond) there will be more no-bond resonating structures, and hence, the compound will be more stable.
Based on the heat of hydrogenation of alkenes, the trend in the stability of carbon-carbon double bonds is: tetrasubstituted > trisubstituted > disubstituted > monosubstituted > unsubstituted.
III is more stable as it contains more hyper conjugation and resonance stabilized. Then IV is stable due to resonance and less hyperconjugation than first. In I and II, α− hydrogen is more in II than first, therefore, II is more stable than first. Therefore the order is: III < IV < II < I
The correct option is B III < IV < II < I
The heat of hydrogenation is inversely proportional to the stability of a compound, hence more stable is the compound, less is its heat of hydrogenation.
There is a phenomenon called Hyperconjugation, which determines stability. According to this factor, if there are more number of Alpha hydrogens, (hydrogens attached to the carbon adjacent to the carbon directly attached with double bond) there will be more no-bond resonating structures, and hence, the compound will be more stable.
Based on the heat of hydrogenation of alkenes, the trend in the stability of carbon-carbon double bonds is: tetrasubstituted > trisubstituted > disubstituted > monosubstituted > unsubstituted.
III is more stable as it contains more hyper conjugation and resonance stabilized. Then IV is stable due to resonance and less hyperconjugation than first. In I and II, α− hydrogen is more in II than first, therefore, II is more stable than first. Therefore the order is: III < IV < II < I
