Question

For the given compounds the correct order of resonance energy is:

• A. $III>I>II$
• B. $II>I>III$
• C. $I>II>III$
• D. $III>II>I$

Answer 1

The correct option is C $I>II>III$

More the number of contributing resonating structures, more will be the resonance energy.



Therefore, the order of resonance energy of the given compounds is:
$I>II>III$

Theory:
The difference in energy between the actual structure (resonance hybrid) and the lowest energy (most stable) resonance structure of a molecule is called resonance enrgy.

If the most stable resonance structure has the energy $E_C$ and the energy of resonance hybrid is $E_O$ then
Resonance Energy, $E_R=E_O-E_C$