Chemistry - GOC Question with Solution | TestHub

IV is aromatic benzene and has a cyclic six-pi-electron delocalized system. $\mathrm{II}$ is a conjugated diene; $\mathrm{III}$ has isolated double bonds; $\mathrm{I}$ is a cumulated diene (allene). Under the hierarchy stated in the question, IV > $\mathrm{II}$ > $\mathrm{III}$ > $\mathrm{I}$. Because these compounds have different formulas, this is a classification of stabilization patterns rather than a ranking of absolute molecular energies.