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General Principles and processes of Isolation of Elements
hard
Incorrect statement in electrolysis of $Al_2O_3$ by Hall-Heroult process is
A
Cryolite $Na_3[AlF_5 ]$ lowers the $m.pt.$ of $Al_2O_3$ and increases its electrical conductivity
B
$Al$ is obtained at cathode and $CO_2$ at anode
C
$Li_2CO_3$ can be used in place of cryolite $(Na_3AlF_6)$
D
$MgF_2$ can be used in place of flourspare $(CaF_2)$
Solution
$Mg^{2+}$ cation will be preferentially discharged than $Al^{3+}$ at cathode.
Standard 12
Chemistry
