91. Which product is formed when acetamide is treated with bromine and sodium hydroxide?
a) Methylamine
b) Aniline
c) Ethylamine
d) Acetanilide
Answer: a) Methylamine
Explanation: The Hoffmann bromamide degradation reaction converts acetamide into methylamine when treated with bromine (Br₂) and sodium hydroxide (NaOH).
92. Which of the following is a correct product for the reaction of aniline with CH₃COCl?
a) Acetaldehyde
b) Acetanilide
c) Aniline acetate
d) Aniline hydrochloride
Answer: b) Acetanilide
Explanation: Aniline reacts with acetyl chloride (CH₃COCl) to form acetanilide, where the amino group (-NH₂) is acetylated to form -NHCOCH₃.
93. Which of the following statements is correct about aromatic amines?
a) They are less basic than aliphatic amines.
b) They are more basic than aliphatic amines.
c) They are strong acids.
d) They are neutral compounds.
Answer: a) They are less basic than aliphatic amines.
Explanation: Aromatic amines, such as aniline, are less basic than aliphatic amines because the lone pair on the nitrogen is delocalized into the aromatic ring, reducing its availability for protonation.
94. The diazonium salt of aniline is stable at:
a) Room temperature
b) Below 5°C
c) Above 50°C
d) 100°C
Answer: b) Below 5°C
Explanation: Diazonium salts are stable at low temperatures, typically below 5°C, because they tend to decompose at higher temperatures, releasing nitrogen gas.
95. Which of the following does not participate in nucleophilic substitution reactions?
a) Nitrobenzene
b) Benzyl chloride
c) Chlorobenzene
d) 2,4-Dinitrochlorobenzene
Answer: a) Nitrobenzene
Explanation: Nitrobenzene is highly deactivated towards nucleophilic substitution reactions due to the electron-withdrawing nature of the nitro group (-NO₂), which reduces the electron density on the aromatic ring.
96. Which of the following reactions converts an amide into an amine with the loss of one carbon atom?
a) Sandmeyer reaction
b) Gabriel synthesis
c) Hoffmann bromamide reaction
d) Diazotization
Answer: c) Hoffmann bromamide reaction
Explanation: The Hoffmann bromamide reaction converts an amide into a primary amine with one less carbon atom by using bromine (Br₂) and sodium hydroxide (NaOH).
97. What is the major product when nitrobenzene is reduced using Sn/HCl?
a) Phenylhydroxylamine
b) Benzylamine
c) Aniline
d) Phenylamine
Answer: c) Aniline
Explanation: When nitrobenzene is reduced using tin (Sn) and hydrochloric acid (HCl), it is converted into aniline (C₆H₅NH₂), where the nitro group (-NO₂) is reduced to an amino group (-NH₂).
98. Which of the following compounds gives a positive Carbylamine test?
a) Methylamine
b) Acetamide
c) Diethylamine
d) Trimethylamine
Answer: a) Methylamine
Explanation: Methylamine, a primary amine, gives a positive Carbylamine test by reacting with chloroform and alcoholic KOH to form methyl isocyanide (CH₃NC), which has a foul odor.
99. Which of the following is the correct decreasing order of basicity for the following amines in the gas phase?
a) (CH₃)₃N > (CH₃)₂NH > CH₃NH₂ > NH₃
b) NH₃ > CH₃NH₂ > (CH₃)₂NH > (CH₃)₃N
c) (CH₃)₂NH > (CH₃)₃N > CH₃NH₂ > NH₃
d) CH₃NH₂ > (CH₃)₃N > (CH₃)₂NH > NH₃
Answer: a) (CH₃)₃N > (CH₃)₂NH > CH₃NH₂ > NH₃
Explanation: In the gas phase, the basicity of amines increases with the number of alkyl groups due to increased electron-donating effects.
100. Which of the following compounds can be used to distinguish between primary, secondary, and tertiary amines?
a) Lucas reagent
b) Benedict’s reagent
c) Hinsberg’s reagent
d) Fehling’s solution
Answer: c) Hinsberg’s reagent
Explanation: Hinsberg’s reagent (benzenesulfonyl chloride) is used to distinguish between primary, secondary, and tertiary amines based on their reactivity and the solubility of the products formed in the reaction
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