Question

Heat of hydrogenation of ethene is x1 and that of benzene is x2. Hence, resonance energy is :

• A. x1 – x2
• B. x1 + x2
• C. 3x1 – x2
• D. x1 – 3x2

Answer 1

Answer: (C)

3x1 – x2

Answer 2

CH2 = CH2 + H2 $\rightarrow$ CH3–CH3

$\Delta$H = X1

So, Hydrogenation energy of benzene sholud be 3x1

$\Delta$H calculated = 3x1

So, Resonance energy = [ 3x1 – x2 ]