Question

Why is benzene an aromatic hydrocarbon?

Answer 1

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.

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.

http://www.wikiwand.com/en/H%C3%BCckel%27s_rule

Best regards;
Hossam…