35 Questions
What term best describes the structure of benzene?
Resonance hybrid
Why is benzene often represented with alternating double bonds in structural formulas?
To simplify electron counting
What is the enthalpy change for the reduction of benzene to cyclohexatriene?
-208 kJ/mol
Which type of reaction does benzene usually prefer over addition reactions?
Substitution
What is essential for aromaticity, according to the information provided?
Cyclic conjugated systems
In the context of benzene stability, what do unusual reactivity and preference for substitution suggest?
High thermal stability
What did Kekulé propose as the structure of benzene?
Cyclohexatriene
Why did Kekulé's earlier theory break when applied to benzene?
Carbon lacked a 4th valence
Why did Kekulé suggest that benzene was in rapid equilibrium between two isomers?
To explain the missing isomer of dibromo benzene
Which type of reaction does benzene undergo due to the stable nature of its resonance hybrid?
Substitution reactions
Why does benzene not react like a typical alkene despite having double bonds in its structure?
Presence of resonance stabilization
How does the presence of delocalized electrons in benzene contribute to its stability?
Enhances its resonance energy
Which technique showed that benzene has a symmetric hexagonal structure?
X-ray diffraction
What is the approximate C-C bond length in benzene?
1.44 Å
Why are chemical resonance hybrids only available for compounds with delocalized electrons?
Delocalized electrons allow for free electron movement
What effect does the freedom of electron movement have on the stability of a molecule?
Increases stability
In a resonance hybrid, which part of the molecule can participate in electron movement?
$\pi$-bonds and lone pairs
What must stay constant in a molecule's resonance hybrid?
Number of electrons
What is the main reason why aromatic compounds are so common in drugs and other applications?
Their ability to form multiple resonance hybrids
Which of the following drugs is NOT classified as an aromatic compound based on the information provided?
Tamoxifen
Based on the lecture, how many out of 100 drugs discussed are aromatic compounds?
86
What role do delocalized electrons play in the stability of aromatic compounds?
They contribute to resonance stabilization, increasing stability
How do aromatic compounds differ from aliphatic compounds in terms of electron movement?
Aromatic compounds demonstrate delocalized electron movement
What aspect of aromatic compounds makes them suitable for applications like medicines and dyes?
Their diverse electron delocalization that enhances stability
What was the name given to the new compound isolated by Faraday from illuminating gas in 1825?
Benzin
How many degrees of unsaturation or ring systems does the molecular formula C6H6 indicate?
4
Who established the molecular formula of benzene (C6H6) based on vapor density?
Mitscherlich
What describes benzene's properties in terms of Resonance Stabilization?
Resonance of pi electrons over all six carbon atoms
How does the chemistry of benzene compare to other 'unsaturated' compounds?
Benzene shows unique stability due to resonance hybridization
What term best describes the structure of benzene in relation to electron movement?
Electron mobility across the ring
Explain the reactivity of benzene towards bromine.
Benzene can be brominated using FeBr3 as a catalyst, leading to substitution reactions.
What was Kekulé's proposal to explain the reactivity of benzene?
Kekulé proposed that benzene exists as two isomers in rapid equilibrium.
Why did Kekulé's earlier theory break when applied to benzene?
Kekulé's earlier theory broke because carbon in benzene needed a 4th valence, contradicting his own theory from 1859.
How does benzene's reactivity differ from that of alkenes?
Benzene does not react like alkenes because it prefers substitution reactions over addition reactions.
What did Kekulé propose to explain the preference for substitution over addition in benzene?
Kekulé suggested that benzene exists as two isomers in rapid equilibrium, accounting for the preference for substitution.
Test your knowledge on the reactivity of benzene in aromatic chemistry. Learn about various reactions involving benzene and how a metal catalyst can lead to bromination. Explore the differences between substitution and addition reactions.
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