The correct statement/statements from the options given below is/are…

The correct answer is Option (3) → (C) only

Note: NTA dropped this question in the official NTA Answer Key. Only statement (C) is true, while Option (3) in the NTA question paper read “(A) and (C) only”. For the benefit of students and to ensure a single answer, Option (3) has been changed to “(C) only”.

Each statement is judged on the chemistry of amines:

• (A) Diazonium salts of aromatic amines are less stable than diazonium salts of aliphatic amines. — Incorrect. It is the other way round: the arenediazonium ion is stabilised by resonance with the benzene ring, so it can be kept in cold solution (273–278 K), while aliphatic diazonium salts decompose at once.

• (B) Ethylamine is insoluble in water. — Incorrect. Lower aliphatic amines are soluble in water because they form hydrogen bonds with water molecules.

• (C) Gabriel phthalimide synthesis can be used to prepare primary amines. — Correct. Phthalimide is converted into its potassium salt, which is heated with an alkyl halide; alkaline hydrolysis then gives the primary amine.

      \( \displaystyle \text{phthalimide} \xrightarrow{\text{ethanolic KOH}} \text{potassium phthalimide} \xrightarrow{\ce{R-X}} \text{N-alkylphthalimide} \xrightarrow{\ce{NaOH(aq)}} \ce{R-NH2} \)

• (D) Because of +R-effect of –\( \ce{NH2} \) group, aniline will undergo Friedel-Crafts acylation reaction. — Incorrect. Aniline does not undergo Friedel–Crafts reactions: its –\( \ce{NH2} \) group forms a salt with the catalyst \( \ce{AlCl3} \), and the nitrogen, now positively charged, deactivates the ring.

NCERT (2026-27 edition):
Gabriel Phthalimide Synthesis