Chemistry Chapter 9 | 2nd Year
Chapter 9 Notes | Chemistry 2nd Year
“Aromatic Hydrocarbons”
- Aromatic hydrocarbons include benzene and all those compounds that structurally related to benzene.
- Aromatic hydrocarbons containing in benzene ring in their molecules are called monocyclic aromatic hydrocarbons.
- Aromatic hydrocarbons containing two or more benzene ring in their molecular formula are called polycyclic aromatic hydrocarbons.
- Benzene was discovered by Michael Faraday in 1825.
- 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.
- Since electrophilic substitutions reaction lead to resonance stabilized because derivatives so substitutions are the main reaction of benzene.
- Resonance energy of benzene is 150.5kj/mole.
- Structure of benzene is the resonance hybrid of two Kekules structure and two Dewar’s structures.
