Bauxite (Al2O3.2H2O) is purified by
AHall-Heroult process using fused electrolyte
BMond's process using carbon monoxide
CBaeyer's process using hot NaOH
DSolvay process using brine and NH3
Answer & Solution
Correct answer: C. Baeyer's process using hot NaOH
1. The chapter section on aluminium ore lists purification methods.
2. Bauxite is treated with hot concentrated NaOH.
3. Al2O3 dissolves as sodium aluminate while Fe2O3 etc. stay behind.
4. This is Baeyer's chemical method.
_Source: Selina Concise Chemistry Class 10, Ch 7 Metallurgy (Mistral OCR'd PDF), section on Bayer's process_
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