Which organic chemical compound is reacted with nitrous acid at 273-274K to prepare benzenediazonium chloride?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. Aniline.
To prepare benzenediazonium chloride, aniline (C₆H₅NH₂) is reacted with nitrous acid (HNO₂) at 273-274 K. Nitrous acid is generated in situ by mixing sodium nitrite (NaNO₂) with hydrochloric acid (HCl). This reaction is known as diazotization and produces C₆H₅N₂Cl (benzenediazonium chloride), a key intermediate in dye and azo compound synthesis. The controlled low temperature (273-274 K) is essential to maintain the stability of the diazonium salt, preventing its decomposition into phenol or nitrogen gas.