Question

______ is prepared by the electrolysis of molten $KH{F}_2$ and anhydrous $HF$.

• A. $H_2$
  
• B. Solid $K$
• C. $F_2$
• D. none of the above

Answer 1

Answer: (C)

$F_2$

Moissan in 1896 prepared $F_2$ as :
$KH{F}_2\rightleftharpoons KF+HF$
$KF\rightleftharpoons K^{\oplus }+F^{\ominus }$
At anode : $2F^{\ominus }\to F_2+2e^{-}$
At cathode : $K^{\oplus }+e^{-}\to K$
$K+2HF\to 2KF+F_2$