Aromatic Compounds Quiz

Aromatic Compounds

• Aromatic compounds are one of the two major classes of organic compounds, the other being aliphatic compounds.

Benzene

• Benzene's molecular formula is C6H6 and it has been known since 1825.
• Benzene has several proposed structures, including Kekule, Dewar, and linear chain structures.

Kekule Structure

• The Kekule structure is a six-membered ring with alternating single and double bonds.
• The Kekule structure is preferred due to several reasons, including:
  • Yields only one substitution product
  • Yields three isomeric distribution products
  • Undergoes substitution rather than addition
  • Carbon-carbon bonds in benzene are equal in length (1.39 Angstrom)

Aromatic Character

• Aromatic compounds have a ring of π orbitals above and below the plane of the molecule.
• The aromatic character of benzene can be predicted by counting the number of π-electrons.
• Huckel's rule states that aromatic properties are expected for planar, cyclic compounds containing 4n+2 π electrons in a closed circuit (where n is a whole number).
• Benzene is an example of an aromatic compound, with six π electrons, satisfying Huckel's rule for n = 1.