Assertion (A) . Energy of resonance hybrid is equal to the average of energines of all canonical forms.
Reason (R). Resonance hybrid cannot be presented by a single structure.

Options

A. Both A and R are correct and R is the correct explanation of A
B. Both A and R are correct but R is not the correct explanation of As
C. both A and R are not correct
D. A is not correct but R is correct

Answer

D

Explanation

A is not correct but R is correct.
Resonance hybrids are always more stable than any of the canonical structures would be, it they existed. The delocalisation of the electrons lowers the orbital energies, imparting stability. The gain in stability of the resonance hybrid over the most stable of the canonical structure is called resonance energy.
A canonical structure that is lower in energy makes a relating greater contribution to resonance hybrid.
Thus, the correct assertion will be energy of resonance hybrid is equal to the sum of energies of all canonical forms in proportion of their contribution towards the resonance hybrid.