Q. Aluminium is extracted from alumina (Al₂O₃) by electrolysis of a molten mixture of
A) Al₂O₃ + KF + Na₃AlF₆
B) Al₂O₃ + HF + NaAlF₄
C) Al₂O₃ + CaF₂ + NaAlF₄
D) Al₂O₃ + Na₃AlF₆ + CaF₂
Explanation
[Solution from source] In the Hall–Héroult process, alumina is electrolysed in molten cryolite (Na₃AlF₆) with fluorspar (CaF₂) added to lower the melting point and raise conductivity. KF, HF and NaAlF₄ are not used. Answer (4).
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.