Question

Which of the following is anti-aromatic in nature?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

(a) Cyclooctatetraene is a cyclic, non-planar (tub-shape) molecule having 8 $\pi$-electrons. Therefore, it is a non-aromatic compound.

(b) Cyclopentadienyl cation is a cyclic, planar molecule having 4 $\pi$-electrons. Therefore, it is an anti-aromatic compound.

(c) Cyclopentadiene is a cyclic, non-planar molecule due to the $s{p}^{3}C$ atom. Therefore, it is a non-aromatic compound.

(d) [10]-Annulene is a cyclic, non-planar molecule having 10 $\pi$-electrons. Therefore, it is a non-aromatic compound.

Hence, option (b) is the correct answer.