MOLECULAR FORMULA AND STRUCTURE OF BENZENE (CBSE 10TH SCIENCE BOARD EXAM QUESTION)

  

The molecular formula of benzene is C₆H₆.

BENZENE

That means:

• 6 carbon atoms

• 6 hydrogen atoms

These atoms are arranged in a ring structure with alternating double bonds, often represented as a hexagon with a circle inside to indicate resonance.

The structure of benzene (C₆H₆) is a planar hexagonal ring made of six carbon atoms, with one hydrogen atom attached to each carbon.

Key Structural Features

• Carbon arrangement: Six carbons form a ring, each bonded to two other carbons and one hydrogen.

• Bonding: Instead of fixed single and double bonds, benzene has resonance—the electrons are delocalized over the whole ring, giving all C–C bonds the same length (~1.39 Å).

• Planarity: All atoms lie in one plane, making it very stable.

• Bond angles: Each carbon is sp² hybridized, with bond angles of 120°.

Common representations:

1. Kekulé structures: Show alternating single and double bonds.

2. Resonance circle: A hexagon with a circle inside to represent delocalized π electrons.

In benzene (C₆H₆), the situation is a bit tricky—there aren’t true fixed single and double covalent bonds.

Why:

• The Kekulé structure shows alternating single and double bonds between carbon atoms.

• In reality, due to resonance, all six C–C bonds are identical: they are intermediate between a single bond and a double bond in strength and length.