Which is the correct order for heat of hydrogenation?

Question

Which is the correct order for heat of hydrogenation? (A) Hept-1-ene < Hept-3-ene < 2-Methylhex-2-ene (B) 3-Methylcyclooctene < 1-Methylcyclooctene < 1,2-Dimethylcyclooctene (C) 3-Ethyloct-1-ene < 2-Ethyloct-1-ene < Oct-2-ene (D) Ethene < ethyne

Tardigrade Admin · Accepted Answer

Heat of hydrogenation propto (1/ text Stability of alkene or crowding across π text bond )

Q. Which is the correct order for heat of hydrogenation?

Hept-1-ene < Hept-3-ene < 2-Methylhex-2-ene

3-Methylcyclooctene < 1-Methylcyclooctene < 1,2-Dimethylcyclooctene

3-Ethyloct-1-ene < 2-Ethyloct-1-ene < Oct-2-ene

Ethene < ethyne

Heat of hydrogenation

$\propto \frac{1}{Stability of alkene or crowding across π bond}$

Q. Which is the correct order for heat of hydrogenation?

Hept-1-ene < Hept-3-ene < 2-Methylhex-2-ene

3-Methylcyclooctene < 1-Methylcyclooctene < 1,2-Dimethylcyclooctene

3-Ethyloct-1-ene < 2-Ethyloct-1-ene < Oct-2-ene

Ethene < ethyne

Heat of hydrogenation ∝ Stability of alkene or crowding across π bond 1​

Heat of hydrogenation

$\propto \frac{1}{Stability of alkene or crowding across π bond}$