Fundamentals of Organic ChemistryChemistryGeneral Organic Chemistry
Which of the following compounds are aromatic? (I) (II) (III) (IV) (V) (VI) (VII) (VIII) (IX) (X) (XI) (XII)
Options
- AI, II, III, IV, V, VI, VIII, X, XII
- BI, II, III, VI, VIII, X, XI, XII
- CI, II, III, IV, V, VI, VII, X, XII
- DI, II, III, V, VII, VIII, IX, X, XII
Correct answer
C. I, II, III, IV, V, VI, VII, X, XII
Step-by-step solution
According to Huckel's rule, a compound is aromatic if it is cyclic, planar, completely conjugated, and contains (4n + 2) electrons. (I) Pyrrole: Contains 2 double bonds (4 electrons) and a lone pair on nitrogen that participates in conjugation. Total = 6 electrons. Aromatic. (II) Imidazole: Contains 2 double bonds and one nitrogen lone pair in a p-orbital participating in conjugation. Total = 6 electrons. Aromatic. (III) Furan: Contains 2 double bonds and one oxygen lone pair participating in conjugation. Total = 6