Aromatic Compounds and Electrophilic Substitution - Advanced Concepts
Q. In the nitration of toluene, which position is most likely to be attacked by the electrophile?
A.Ortho position
B.Meta position
C.Para position
D.All positions equally
Solution
The para position is favored in the nitration of toluene due to the electron-donating effect of the methyl group, which stabilizes the carbocation intermediate.
Correct Answer: C — Para position
Q. What is the IUPAC name of the compound with the structure C6H5-CH2-COOH?
A.Benzyl acetic acid
B.Phenylacetic acid
C.Benzenepropanoic acid
D.Benzeneacetic acid
Solution
The correct IUPAC name is phenylacetic acid, as it consists of a phenyl group attached to an acetic acid moiety.
Correct Answer: B — Phenylacetic acid
Q. What is the major product when anisole (methoxybenzene) undergoes nitration?
A.Nitroanisole (ortho)
B.Nitroanisole (para)
C.Dinitroanisole
D.Anisole
Solution
The major product is para-nitroanisole due to the electron-donating effect of the methoxy group, which directs the electrophile to the para position.
Correct Answer: B — Nitroanisole (para)
Q. What is the product of the reaction of phenol with excess bromine?
A.Bromobenzene
B.2,4,6-Tribromophenol
C.Bromophenol
D.Benzene
Solution
The product is 2,4,6-tribromophenol, as phenol is highly reactive towards electrophilic substitution and can undergo multiple brominations.
Correct Answer: B — 2,4,6-Tribromophenol
Q. Which of the following compounds is a meta-directing group in electrophilic aromatic substitution?
A.Amino group (-NH2)
B.Methyl group (-CH3)
C.Nitro group (-NO2)
D.Hydroxyl group (-OH)
Solution
The nitro group (-NO2) is a meta-directing group because it withdraws electrons from the aromatic ring, making the ortho and para positions less favorable for electrophilic attack.
Correct Answer: C — Nitro group (-NO2)
Q. Which of the following compounds is an example of a polycyclic aromatic hydrocarbon?
A.Naphthalene
B.Benzaldehyde
C.Toluene
D.Phenol
Solution
Naphthalene is a polycyclic aromatic hydrocarbon, consisting of two fused benzene rings.
Correct Answer: A — Naphthalene
Q. Which of the following reactions is an example of Friedel-Crafts acylation?
A.Benzene + CH3Cl in AlCl3
B.Benzene + CH3COCl in AlCl3
C.Benzene + HNO3 in H2SO4
D.Benzene + Br2 in FeBr3
Solution
Benzene + CH3COCl in AlCl3 is an example of Friedel-Crafts acylation, where an acyl group is introduced to the aromatic ring.
Correct Answer: B — Benzene + CH3COCl in AlCl3
Q. Which of the following statements about electrophilic aromatic substitution is true?
A.The aromatic ring acts as a nucleophile.
B.The electrophile is generated in situ.
C.Both ortho and para products are formed equally.
D.The reaction requires a strong base.
Solution
In electrophilic aromatic substitution, the aromatic ring acts as a nucleophile, attacking the electrophile to form a sigma complex.
Correct Answer: A — The aromatic ring acts as a nucleophile.
Q. Which of the following substituents on a benzene ring is a strong electron-donating group?
A.Nitro group (-NO2)
B.Hydroxyl group (-OH)
C.Carboxyl group (-COOH)
D.Methyl group (-CH3)
Solution
The hydroxyl group (-OH) is a strong electron-donating group due to resonance, enhancing the nucleophilicity of the benzene ring.
