Chemistry Chapter 9 | 2nd Year

 Chapter 9 Notes | Chemistry 2nd Year

“Aromatic Hydrocarbons”

1. Aromatic hydrocarbons include benzene and all those compounds that structurally related to benzene.
2. Aromatic hydrocarbons containing in benzene ring in their molecules are called monocyclic aromatic hydrocarbons.
3. Aromatic hydrocarbons containing two or more benzene ring in their molecular formula are called polycyclic aromatic hydrocarbons.
4. Benzene was discovered by Michael Faraday in 1825.
5. The electrons in benzene are loosely held and the ring acts as a source of electrons. Hence benzene is readily attacked by electrophiles in the presence of catalyst.
6. Since electrophilic substitutions reaction lead to resonance stabilized because derivatives so substitutions are the main reaction of benzene.
7. Resonance energy of benzene is 150.5kj/mole.
8. Structure of benzene is the resonance hybrid of two Kekules structure and two Dewar’s structures.

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