Question

Find out F in the given flowchart.

• A. cathode
• B. anode
• C. electrolyte
• D. none of these

Answer 1

The correct option is A cathode

Al is extracted by the electrolysis of fused mixture of alumina, cryolite and fluorspar.

The reaction involved in the whole process is given as :

$A{l}_2{O}_3.2H_{2}O\stackrel{conc.N{a}_{2}C{O}_3}{\to }Na\left[Al\right(OH{)}_4]\stackrel{C{O}_2}{\to }A{l}_2{O}_3\stackrel{MixwithN{a}_{3}Al{F}_6}{\to }Al$

A B C D E F

At cathode, Al(III) ions are oxidized to Al and at anode, fluoride ions are reduced to fluorine.
At cathode $4A{l}^{+}+12e^{-}\to 4Al$
At anode $12F^{-}\to 6F_2+12e^{-}$

Hence, F is $cathode$.