Question

A molecule may be represented by three structures having energies $E_1,E_2$ and $E_3$, respectively. The energies of these structures follow the order $E_3<E_2<E_1$ respectively. If the experimental bond energy of the molecule is $E_0$, the resonance energy is:

• A. $(E_1+E_2+E_3)-E_0$
• B. $E_0-E_3$
• C. $E_0-E_1$
• D. $E_0-E_2$

Answer 1

The correct option is B $E_0-E_3$

Resonance stabilizes the molecule or ion as the energy of the resonance hybrid (actual structure of the molecule or ion) is less than the energy of any single cannonical structure. The difference in energy between the actual structure (E0)(E0) and the lowest energy resonance structure (E3)(E3) is called the resonance stabilization energy or simply the resonance energy

hence

resonanceenergy=Eo-E3