Benzenediazonium chloride is treated with HBF4 and the precipitate is filtered, dried and heated. The products are

JEE Main levelSingle correct optionDifficulty 2 of 3nc060

Benzenediazonium chloride is treated with $HBF X_{4}$ and the precipitate is filtered, dried and heated. The products are

HBF X_{4}

gives the insoluble benzenediazonium tetrafluoroborate,

C X_{6} H X_{5} N X_{2} X^{+} BF X_{4} X^{-}

. On heating (Balz-Schiemann reaction) it decomposes to

C X_{6} H X_{5} F

N X_{2}

and

BF X_{3}

; the fluorine comes from

BF X_{4} X^{-}

, and no chloride is involved in this step.