Why is benzene an aromatic hydrocarbon?

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Answer 1 · 2015-02-09T20:00:52

Benzene is an aromatic hydrocarbon because it obeys Hückel's rule.

Originally, benzene was considered aromatic because of its smell: it has an "aromatic" odor.

It is now considered aromatic because it obeys Hückel's rule:

#4n + 2# = number of π electrons in the hydrocarbon, where #n# must be an integer.

In the case of benzene, we have 3 π bonds (6 electrons), so #4n + 2 = 6#.

#n = 1# (an integer). So, benzene is aromatic.

Another example is naphthalene, with two fused benzene rings.

Fused benzene rings from www.pherobase.com.

It has 5 π bonds and 10 electrons.

#4n + 2 = 10#. So, #n = 2# (an integer).

So, naphthalene is aromatic…

This link should help you.

Best regards;
Hossam…