Take this Quiz: A-Level Chemistry: Aromatic Chemistry and Amines | Zestly

Question 1

Which experimental evidence most strongly supports the delocalised model of benzene over the Kekulé structure?

Accepted Answer

The enthalpy of hydrogenation of benzene is significantly less exothermic than three times that of cyclohexene.

Question 2

In the nitration of benzene, which species acts as the electrophile and what is the role of concentrated sulfuric acid?

Accepted Answer

The electrophile is NO2+ and sulfuric acid acts as a catalyst to generate the electrophile.

Question 3

Which of the following statements correctly describe the basicity of amines?

Accepted Answer

Aliphatic amines are stronger bases than ammonia due to the electron-releasing inductive effect of alkyl groups.

Question 4

Why does benzene undergo electrophilic substitution rather than electrophilic addition?

Answer

Addition reactions are too fast to control.

Answer

Substitution is more exothermic than addition.

Answer

Addition would require higher temperatures than substitution.

Answer

Substitution preserves the stable delocalised pi-electron system of the benzene ring.

Question 5

Which reagents and conditions are required for the Friedel-Crafts acylation of benzene?

Answer

An acyl chloride and a dilute aqueous acid catalyst.

Answer

An acyl chloride and an anhydrous AlCl3 catalyst.

Answer

An alcohol and a concentrated sulfuric acid catalyst.

Answer

An alkene and a nickel catalyst.