JEE Main · 2026 · 08 Apr 2026 · Shift 2 · General Organic Chemistry

A species is aromatic when it is cyclic, planar, fully conjugated and carries $(4n+2)\pi$ electrons. Among the given species the cyclopropenyl cation ($2\pi$), the cyclobutadienyl dication ($2\pi$), the cyclopentadienyl anion ($6\pi$) and the tropylium (cycloheptatrienyl) cation ($6\pi$) each meet this requirement and are aromatic. p-Benzoquinone is cross-conjugated through its carbonyl groups and has no closed $(4n+2)\pi$ ring, the cyclohexadienyl anion has an $s{p}^3$ carbon that breaks the ring conjugation, and the cycloheptatrienyl anion has $8\pi$ electrons ($4n$); these are not aromatic. Four of the given species are aromatic.