Chemistry - GOC Question with Solution | TestHub

(a) phenol : aromatic. (b) the four-membered ring with 4 π electrons : anti-aromatic. (c) hexa-1,3,5-triene : acyclic, non-aromatic. (d) the 4H-pyranylium-type cation has 4 π electrons from the C=C bonds + 2 from the O lone pair = 6 : aromatic. (e) cyclohexene : non-aromatic. (f) cyclohexa-1,3-diene ($s{p}^3$ carbons) : non-aromatic. (g) naphthalene : aromatic. (h) the three-membered and five-membered rings combine in a dipolar form, a cyclopropenyl cation (2π) and a cyclopentadienyl anion (6π) : aromatic.

Here (d) and (h) are counted as aromatic (the book calls them quasi-aromatic). Aromatic : a, d, g, h = 4.