Kekule's structure refers to the cyclic hexagonal model proposed by the German chemist Friedrich August Kekule in 1865 to explain the structure of benzene, the simplest aromatic hydrocarbon. In this model, benzene is depicted as a ring of six carbon atoms, with alternating single and double bonds between them, resulting in a formula of C₆H₆. This structure suggested that benzene could undergo substitution reactions rather than addition reactions, preserving its aromaticity. However, Kekule's model was later refined to incorporate the concept of resonance, which explains that the actual structure of benzene is a resonance hybrid of multiple contributing structures, leading to equal bond lengths and enhanced stability, contrary to the alternating bond lengths suggested by his original model.
Who proposed the structure of benzene known as Kekule's structure?
The structure was proposed by the German chemist Friedrich August Kekule in 1865.
What is the basic arrangement of atoms in Kekule's structure of benzene?
Kekule's structure depicts benzene as a cyclic hexagonal ring of six carbon atoms with alternating single and double bonds.
How does Kekule's structure explain the reactivity of benzene?
Kekule's structure suggests that benzene undergoes substitution reactions rather than addition reactions, which helps maintain its aromatic character.
What was a significant limitation of Kekule's structure?
A significant limitation was that it implied alternating single and double bonds, which suggested different bond lengths, whereas experimental evidence shows that all C-C bond lengths in benzene are equal.
How did Kekule's structure contribute to the understanding of aromatic compounds?
Kekule's structure was pivotal in establishing the concept of aromaticity and helped chemists understand the unique stability and reactivity of benzene and related compounds.
Who proposed the cyclic hexagonal structure of benzene?
a) Dmitri Mendeleev
b) Friedrich August Kekule
c) Linus Pauling
d) Robert H. Grubbs
Answer: b) Friedrich August Kekule
What is the molecular formula of benzene according to Kekule's structure?
a) C₆H₆
b) C₆H₁₂
c) C₆H₄
d) C₆H₈
Answer: a) C₆H₆
In Kekule's structure, how are the carbon atoms arranged?
a) Linear
b) Tetrahedral
c) Cyclic hexagonal
d) Triangular
Answer: c) Cyclic hexagonal
What type of reactions does benzene primarily undergo according to Kekule's structure?
a) Addition reactions
b) Substitution reactions
c) Elimination reactions
d) Rearrangement reactions
Answer: b) Substitution reactions
What is a significant limitation of Kekule's structure?
a) It does not explain the stability of benzene.
b) It suggests different bond lengths for C-C bonds.
c) It cannot account for resonance.
d) It implies benzene is a straight-chain hydrocarbon.
Answer: b) It suggests different bond lengths for C-C bonds.