Which of the following molecules is least resonance stabilized ?
(A)(see structure)benzene
(B)(see structure)furan
(C)(see structure)pyridine✓ Correct
(D)(see structure)cyclohexadienone
Answer: (C)
Solution
Aromatic rings are heavily resonance-stabilised because their π electrons delocalise around a closed, planar loop obeying the 4n+2 rule — true of benzene, furan and pyridine alike. The cyclohexadienone, by contrast, has its carbonyl breaking that cyclic conjugation, so it carries the least resonance stabilisation of the set.
JEE Main · 2017 · 02 Apr 2017 · Offline · Single correct option