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General Principles and processes of Isolation of Elements
medium
Aluminium is extracted from alumina $(Al_2O_3)$ by electrolysis of a molten mixture of
A
$Al_2O_3 + HF + NaAlF_4$
B
$Al_2O_3 + CaF_2 + NaAlF_4$
C
$Al_2O_3 + Na_3AlF_6 + CaF_2$
D
$Al_2O_3 + KF + Na_3AlF_6$
(AIPMT-2012)
Solution
Alumina, $A l_{2} O_{3}$ is a bad conductor of electricity and has very high melting point, so before subjecting to electrolysis, it is mixed with fluorspar $\left(C a F_{2}\right)$ and cryolite $\left(N a_{3} A l F_{6}\right),$ which lower its melting point and make it more conducting. Mainly $C a F_{2}$ and $N a_{3} A l F_{6}$ mixed with $A l_{2} O_{3}$ for converting in molten state.
Standard 12
Chemistry
Similar Questions
Match items of Column $I$ with the items of Column $II$ and assign the correct code :
Column $I$ | Column $II$ |
$(A)$ Cyanide process | $(i)$ Ultrapure $Ge$ |
$(B)$ Froth floatation | $(ii)$ Dressing of $ZnS$ process |
$(C)$ Electrolytic | $(iii)$ Extraction of $Al$ reduction |
$(D)$ Zone refining | $(iv)$ Extraction of $Au$ |
$(v)$ Purification of $Ni$ |
code :