MEDIUMMCQ SINGLEIChO (Chemistry Olympiad)Inorganic ChemistryMetallurgyExtraction of Aluminium
The major role of fluorspar (CaF₂) which is added in small quantities in the electrolytic reduction of alumina dissolved in fused cryolite (Na₃AlF₆) is
A.as a catalyst
B.to make the fused mixture very conducting✓ Correct
C.to increase the temperature of the melt
D.to decrease the rate of oxidation of carbon at the
Explanation
Aluminium is extracted from alumina by electrolysis. But the alumina is a bad conductor of electricity so the alumina is added with cryolite and fluorspar to increase the conductivity of the mixture and it also decreases the melting point of the mixture.