question_answer

Which of the following is not aromatic?

A)  Benzene

B)  Cyclopropenyl cation

C)  Tropylium cation

D)  Cyclopentadienyl cation

E)  Cyclopentadienyl anion

Correct Answer: D

Solution :

                Cyclopentadienyl cation is not aromatic compound. Cyclic compound with\[(4n)\pi {{e}^{-}}\]are anti aromatic compound. Cyclopentadienyl cation has \[4\pi {{e}^{-}},\] hence it is an anti aromatic compound.