Aryl fluoride can be obtained directly by heating which arenediazonium salt?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → Benzenediazonium fluoroborate
When benzenediazonium chloride is treated with fluoroboric acid, benzenediazonium fluoroborate precipitates. On heating, this salt decomposes to give the aryl fluoride:
\( \displaystyle \ce{C6H5N2^+Cl^- + HBF4 -> C6H5N2^+BF4^- v + HCl} \)
\( \displaystyle \ce{C6H5N2^+BF4^-} \xrightarrow{\Delta} \ce{C6H5F + BF3 + N2 ^} \)
NCERT (2026-27 edition):
9.9 Chemical Reactions – “3. Replacement by fluoride ion: When arenediazonium chloride is treated with fluoroboric acid, arene diazonium fluoroborate is precipitated which on heating decomposes to yield aryl fluoride.”