Unit 9: Aromatic Hydrocarbons

41. Which of the following reactions involves the addition of a halogen to an aromatic ring?

a) Friedel-Crafts alkylation
b) Halogenation
c) Nitration
d) Sulfonation
Answer: b) Halogenation

42. The main difference between alkenes and aromatic hydrocarbons is:

a) The presence of a benzene ring in aromatic hydrocarbons
b) The type of bonds in the hydrocarbons
c) The molecular formula
d) The reaction conditions
Answer: a) The presence of a benzene ring in aromatic hydrocarbons

43. The process by which benzene is converted to cyclohexane is called:

a) Hydrogenation
b) Halogenation
c) Nitration
d) Sulfonation
Answer: a) Hydrogenation

44. The presence of which group makes phenol more reactive than benzene in electrophilic substitution reactions?

a) Hydroxyl group
b) Methyl group
c) Nitro group
d) Carboxyl group
Answer: a) Hydroxyl group

45. Which aromatic compound is known for its use in producing TNT (trinitrotoluene)?

a) Benzene
b) Toluene
c) Phenol
d) Aniline
Answer: b) Toluene

46. The term “aromatic” refers to:

a) The pleasant smell of aromatic compounds
b) The presence of a benzene ring or similar structure
c) The high reactivity of the compounds
d) The ability to form multiple bonds
Answer: b) The presence of a benzene ring or similar structure

47. In the reaction of phenol with an alkyl halide, the product is:

a) Alkylphenol
b) Phenylalkane
c) Alkylbenzene
d) Phenyl ether
Answer: a) Alkylphenol

48. Which aromatic compound is a known carcinogen and is regulated due to health concerns?

a) Benzene
b) Toluene
c) Xylene
d) Aniline
Answer: a) Benzene

49. The reactivity of aromatic hydrocarbons towards electrophilic substitution reactions is due to:

a) The stability of the aromatic ring
b) The presence of a carbonyl group
c) The presence of hydroxyl groups
d) The high electronegativity of the ring
Answer: a) The stability of the aromatic ring

50. The reaction of an aromatic hydrocarbon with a carboxyl group and an alkyl group is called:

a) Friedel-Crafts alkylation
b) Friedel-Crafts acylation
c) Sulfonation
d) Nitration
Answer: b) Friedel-Crafts acylation