In which of the following pairs does the first compound (I) have more resonance energy than the second (II) ?
(A) (I) (II)
(B) (I) (II)
(C) (I) (II)
(D) (I) (II)

Question

In which of the following pairs does the first compound (I) have more resonance energy than the second (II) ? (A) (I) (II) (B) (I) (II) (C) (I) (II) (D) (I) (II)

TestHub · Accepted Answer

(A) butadiene is acyclic and has far less resonance energy than benzene. (B) pyrrole (resonance energy about 21 kcal/mol) has more resonance energy than furan (about 16 kcal/mol) : correct. (C) the cyclohexadienyl cation (4π, anti-aromatic when planar) is destabilised, while the tropylium cation is aromatic (6π). (D) cyclooctatetraene is non-planar with almost no resonance, while styrene has a benzene ring. So (B).

Chemistry - GOC Question with Solution | TestHub

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