Chemistry - GOC Question with Solution | TestHub

(I) the cyclopentadienyl anion has 6π : aromatic. (II) cyclobutadiene has 4π : anti-aromatic. (III) cyclopentadiene has an $\mathrm{s}{\mathrm{p}}^3$ $\mathrm{C}{\mathrm{H}}_2$ : non-aromatic. (IV) the cycloheptatrienyl radical has 7π : not aromatic. Only (I).