(B) Cryolite is $Na_3AlF_6$. In the Hall-$H$éroult process,pure alumina $(Al_2O_3)$ has a very high melting point $(2323 \ K)$. Adding cryolite $(Na_3

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$Na_3AlF_6$ and is used to decrease the melting point of alumina in the electrolysis of alumina.

(B) Cryolite is $Na_3AlF_6$. In the Hall-$H$éroult process,pure alumina $(Al_2O_3)$ has a very high melting point $(2323 \ K)$. Adding cryolite $(Na_3AlF_6)$ lowers the melting point of the mixture to about $1240 \ K$ and also increases the electrical conductivity of the melt,making the electrolysis process more efficient.

Class 12 Chemistry General Principles and Processes of Isolation of Elements Reduction to free Metal

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Cryolite is .........

A
$Na_3AlF_6$ and is used to decrease the electrical conductivity in the electrolysis of alumina.
B
$Na_3AlF_6$ and is used to decrease the melting point of alumina in the electrolysis of alumina.
C
$Na_3AlF_6$ and is used for the electrolytic refining of alumina.
D
$Na_3AlF_6$ and is used in the electrolysis of alumina.