Kekule's benzene model originally proposed which bonding pattern?

Kekule's benzene model originally proposed which bonding pattern?

• A. Kekule proposed benzene has alternating single and double bonds
• B. Kekule proposed benzene has only single bonds
• C. Kekule proposed benzene has three double bonds and three singles
• D. Kekule proposed benzene has no resonance

Answer: (A)

Kekulé tried to fit benzene’s ring with carbon’s valence by placing bonds in an alternating pattern around the ring. This means three double bonds and three single bonds arranged in succession around the six-member ring, so each carbon forms bonds to its two ring neighbors and to a hydrogen. This arrangement accounts for the ring structure and the molecular formula C6H6. Later observations showed all the carbon–carbon bonds are of similar length, which is explained by resonance and electron delocalization across the ring, but Kekulé’s original idea was the alternating single and double bonds around the ring.

Kekulé tried to fit benzene’s ring with carbon’s valence by placing bonds in an alternating pattern around the ring. This means three double bonds and three single bonds arranged in succession around the six-member ring, so each carbon forms bonds to its two ring neighbors and to a hydrogen. This arrangement accounts for the ring structure and the molecular formula C6H6. Later observations showed all the carbon–carbon bonds are of similar length, which is explained by resonance and electron delocalization across the ring, but Kekulé’s original idea was the alternating single and double bonds around the ring.