Question

Of these compounds, which compound has minimum heat of hydrogenation per $\pi$ -bond?

• A. cis-2-butene
• B. trans-2-butene
• C. 2, 3-dimethyl-2-butene
• D. benzene

Answer 1

Answer: (D)

Heat of hydrogenation $\propto \frac{\text{1}}{\text{stability}\text{of}\text{compound}}$

Benzene is most stable because it is aromatic so it will have least heat of hydrogenation.