Question

Which of the following statements about \(C_6H_5N_2BF_4\) are correct? I. With NaF gives \(C_6H_5F\) II. With NaNO\(_2\)/Cu gives \(C_6H_5NO_2\) III. On heating gives \(C_6H_5F\) IV. With HNO\(_3\) gives \(C_6H_5NO_2\)

• A. I, II only
• B. II, III only
• C. I, IV only
• D. III, IV only

Hint:

Balz–Schiemann reaction is the standard method to convert diazonium salts into aryl fluorides.

Answer 1

The Correct Option is A

Concept: Aryl diazonium tetrafluoroborate salts undergo substitution reactions where the diazonium group is replaced by different nucleophiles.

Step 1: Reaction with NaF. Balz–Schiemann reaction: \[ C_6H_5N_2^+BF_4^- \xrightarrow{NaF} C_6H_5F \] Thus statement I is correct.

Step 2: Reaction with NaNO\(_2\)/Cu. Gives nitrobenzene: \[ C_6H_5NO_2 \] Thus statement II is correct.

Step 3: Heating reaction. Thermal decomposition usually gives fluorobenzene. Thus III is incorrect in this context.

Step 4: Reaction with HNO\(_3\). Direct nitration is not characteristic transformation of diazonium BF\(_4\) salt. Thus IV incorrect.

Step 5: Final conclusion. Correct statements: \[ I,\;II \] Hence: \[ \boxed{A} \]