Question

Indicate whether or not each of the following structures is considered to be aromatic.

Indicate whether or not each of the following structures is considered to be aromatic. A is aromatic, B is not. B is aromatic, A is not. Both A and B are aromatic. A and B are not aromatic.

Answer 1

Concepts and reason

The concept used to solve this problem is to determine aromatic compound with the help of Huckel's rule.

Fundamentals

The compound which has continuous cyclic structure with electrons, where are called aromatic compound.

The compound which has continuous cyclic structure with electrons, where are called Anti-aromatic.

The compounds which does not have any planarity, that is, they are non-planar are said to be non-aromatic.

Aromatic compound follows Huckel's rule.

According to the Huckel's rule compound should have stratified following conditions:

1.Compound contains electrons in their structure where n is the integer number like 0,1, 2 etc.

2.Carbons of compound should be in hybridization state.

3.Compound must be cyclic, non cyclic compound is not aromatic.

4.Compound contains conjugation means alternative single and double bonds.

The structure of given compounds are as follows:

Compound A

Compound B

Compound A contains three double bond means total 6 π electrons.

Compound B There are the 4 electrons would be from the double bonds and one of the lone pair from the oxygen would be involved in conjugation so total 6pi electrons.

Compound A

Compound A is not an example of aromatic compound because it is not planar molecule.

Compound B

Compound B is an example of aromatic compound.

Ans:

Thus, compound B is aromatic while A is not.