Practice Problem: Aromaticity

The video tutorial explains aromaticity, focusing on the criteria for a molecule to be aromatic: it must be planar, fully conjugated, and satisfy Huckel's rule. The instructor analyzes several molecules, identifying which are aromatic, non-aromatic, or anti-aromatic. Special attention is given to heterocycles, where lone pairs may or may not participate in conjugation to achieve aromaticity.

Which of the following is NOT a criterion for a molecule to be aromatic?

• The molecule must have an odd number of π electrons.

• The molecule must be fully conjugated.

• The molecule must satisfy Huckel's rule.

• The molecule must be completely planar.

What is the number of π electrons required for a molecule to satisfy Huckel's rule when n=1?

• 4

• 8

• 2

• 6

Why is a molecule with 10 π electrons considered aromatic?

• It contains a heteroatom.

• It is fully conjugated and planar.

• It satisfies Huckel's rule with n=2.

• It has an odd number of π electrons.

What makes a compound anti-aromatic?

• It contains a heteroatom.

• It has a number of π electrons that does not satisfy Huckel's rule.

• It is not fully conjugated.

• It is not planar.

Which of the following π electron counts would make a compound anti-aromatic?

• 8

• 10

• 6

• 12

How can lone pairs in heterocycles affect aromaticity?

• They only participate if the heterocycle is non-planar.

• They may or may not participate in conjugation depending on the need for aromaticity.

• They never participate in conjugation.

• They always participate in conjugation.

In a heterocycle, what happens if a lone pair does not participate in conjugation?

• The molecule can still be aromatic if other criteria are met.

• The molecule becomes a radical.

• The molecule becomes anti-aromatic.

• The molecule becomes non-aromatic.