Question

Choose the correct statement:

• A. Aliphatic amines are weaker bases than NH\(_3\) while aromatic amines are stronger bases than NH\(_3\).
• B. Gabriel phthalimide synthesis is used for preparing both Ethyl amine and Aniline.
• C. Anilinium ion is less resonance stabilized than Aniline.
• D. Sec-butylamine is optically inactive because Nitrogen atom of the \( \text{–NH}_2 \) group is achiral.

Hint:

Resonance stabilization in amines can affect their basicity. In aromatic amines, the lone pair of electrons on nitrogen is delocalized into the ring, reducing their ability to act as a base.

Answer 1

The Correct Option is C

Step 1: Analyze Option (A).
Aliphatic amines, due to the electron-donating nature of the alkyl group, are indeed weaker bases than ammonia (NH\(_3\)). Aromatic amines, on the other hand, have their lone pair of electrons on nitrogen delocalized into the aromatic ring, making them weaker bases than aliphatic amines but still stronger than ammonia. Therefore, this option is correct.

Step 2: Analyze Option (B).
Gabriel phthalimide synthesis is used to prepare primary amines, especially for an amine like ethylamine. However, it is not used to prepare aniline directly. Aniline is typically prepared by reducing nitrobenzene or by other synthetic routes. Therefore, this statement is incorrect.

Step 3: Analyze Option (C).
Anilinium ion (\( \text{C}_6\text{H}_5\text{NH}_3^+ \)) is less resonance stabilized than aniline because the positive charge on the nitrogen prevents the lone pair of electrons from participating in resonance with the aromatic ring. This reduces the resonance stabilization, making the statement correct.

Step 4: Analyze Option (D).
Sec-butylamine is optically inactive, but not due to the achirality of the nitrogen. The nitrogen in sec-butylamine has a non-superimposable mirror image (as it is attached to two distinct groups), so it could be chiral. The correct reason for optical inactivity is that the amine group itself does not create chirality in this molecule. Therefore, this statement is incorrect.

Step 5: Conclusion.
The correct answer is (C) Anilinium ion is less resonance stabilized than Aniline.