Question

What are aromatic hydrocarbons? Give a detailed description of the bonding in benzene. The$\mathrm{\pi }$electrons in benzene are delocalized, whereas the$\mathrm{\pi }$electrons in simple alkenes and alkynes are localized. Explain the difference.

Short answer

Aromatic hydrocarbons are a category of organic compounds in which benzene is the parent molecule and entirely consists of carbon and hydrogen atoms.

The position of their atoms determines the difference between $\mathrm{\pi }$electrons from the benzene atomic link and $\mathrm{\pi }$electrons in simple alkenes and alkynes.

Step-by-step solution

Aromatic hydrocarbons

A hydrocarbon with one or more benzene ring, whichisfound in the benzene family of organic compounds,is calledan aromatic hydrocarbon.

It is a colorless liquid hydrocarbon that is highly flammable and carcinogenic.A hydrocarbon is carbon and hydrogen-based organic molecule. Benzene, toluene, and xylene are a few examples.

Bonding in the benzene ring 

In a benzene’s six-membered ring configuration, a benzene has six carbons and six hydrogens. All carbon atoms in a benzene are connected with theirhybrid orbitals.

Representation of benzene ring

Orbitals that haven't been hybridized collide to produce$\mathrm{\pi }$ bonds. As a result, each carbon atom will have one free $\mathrm{\pi }$ orbital. These electron concentrations will exist on both sides of the benzene ring.

On the other hand, in simple alkenes and alkynes, a double carbon-carbon bond cannot move across the ring. Hence, there is no delocalization.