Consider the following list of cyclic compounds: (A) Cyclooctatetraene (B) [10]-annulene (C) Cyclopentadienyl anion (D) Tropylium cation (E) Pyrrole (F) Pyridine The total number of aromatic compounds among the above is:

Step-by-step solution

To determine aromaticity, a compound must be cyclic, planar, fully conjugated, and have (4n+2) electrons. 1. Cyclooctatetraene has 8 electrons ( 4n rule) and adopts a non-planar tub shape to avoid anti-aromaticity, making it non-aromatic. 2. [10]-annulene has 10 electrons but suffers from severe steric repulsion between its internal trans hydrogens, forcing the ring to twist out of planarity. Hence, it is non-aromatic. 3. Cyclopentadienyl anion has 6 electrons and is planar, hence it is aromatic. 4. Tropylium catio