Chemistry - GOC Question with Solution | TestHub

$\mathrm{C}-\mathrm{I}$ ionization of $\mathrm{III}$ produces an allylic carbocation; its positive charge is shared between two ring positions. $\mathrm{II}$ gives an ordinary secondary cyclopentyl cation without pi resonance. $\mathrm{I}$ would give a fully conjugated cyclopentadienyl cation with four pi electrons, which is antiaromatic if planar and is disfavored. Thus, for carbocation-forming ionization, $\mathrm{III}$ > $\mathrm{II}$ > $\mathrm{I}$. The corrected key is $\mathrm{C}$.