Benzene is a planar, cyclic molecule with delocalized $$\\pi$$ electrons shared equally among all six carbon atoms.

$$\\mathrm{C_6H_6} + \\mathrm{$$HNO_3$$} \\xrightarrow{\\mathrm{H_2SO_4}} \\mathrm{C_6H_5NO_2} + \\mathrm{H_2O}$$

Question 1

Which of the following best describes the structure of benzene according to the resonance model?

Accepted Answer

Benzene is a planar, cyclic molecule with delocalized $$\pi$$ electrons shared equally among all six carbon atoms.

Question 2

Which reaction is characteristic of benzene rather than alkenes?

Accepted Answer

Electrophilic aromatic substitution, such as nitration.

Question 3

What is the main reason benzene undergoes substitution reactions rather than addition reactions?

Accepted Answer

Substitution reactions preserve the aromatic stability of benzene.

Question 4

Which of the following is the correct equation for the nitration of benzene?

Accepted Answer

$$\mathrm{C_6H_6} + \mathrm{$$HNO_3$$} \xrightarrow{\mathrm{H_2SO_4}} \mathrm{C_6H_5NO_2} + \mathrm{H_2O}$$

Question 5

During electrophilic aromatic substitution, what is the role of the electrophile?

Accepted Answer

It replaces a hydrogen atom on the benzene ring.

Question 6

Which of the following best explains why phenol is more reactive than benzene towards electrophilic substitution?

Accepted Answer

The hydroxyl group donates electrons to the ring, increasing electron density.

Question 7

Which of the following is a correct mechanism step in the electrophilic substitution of benzene?

Accepted Answer

Formation of a carbocation intermediate after the electrophile attacks the ring.

Question 8

A student mixes benzene with bromine in the presence of iron(III) bromide. What is the expected product?

Accepted Answer

Bromobenzene and hydrogen bromide

Question 9

Which of the following statements about the Kekulé and resonance models of benzene is correct?

Accepted Answer

The resonance model explains the delocalization of electrons and equal bond lengths.

Question 10

Which of the following best describes the effect of the hydroxyl group on the acidity of phenol compared to benzene?

Accepted Answer

Phenol is more acidic than benzene because the hydroxyl group stabilizes the phenoxide ion.

Question 11

Which of the following is a real-world application of electrophilic aromatic substitution?

Accepted Answer

Synthesis of nitrobenzene, a precursor for aniline used in dyes and pharmaceuticals.

Question 12

Which equation represents the formation of phenol from benzene in industry?

Accepted Answer

$$\mathrm{C_6H_6} \xrightarrow{\mathrm{O_2$, H_2SO_4}} \mathrm{C_6H_5OH}$$

Question 13

A chemist wants to synthesize bromobenzene from benzene. Which reagents and conditions should be used?

Accepted Answer

Bromine and iron(III) bromide catalyst

Question 14

Which of the following best explains why benzene is less reactive than alkenes towards bromine?

Accepted Answer

Benzene's delocalized electrons provide extra stability, making it less reactive.

Question 15

Which of the following is the correct order of reactivity towards electrophilic substitution: benzene, phenol, toluene?

Accepted Answer

Phenol \u003e Toluene \u003e Benzene

Arenes and Benzene: Structure, Reactions, and Mechanisms

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