Same chapter3 marksDifficulty: Medium
Name the constituents and one use of brass, bronze and duralumin.
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3 marksDifficulty: Medium
Name the chief ore of aluminium and describe how the ore is concentrated by Baeyer's process.
Original Khojo Papers practice question — not from a past board paper.
Answer
The chief ore is bauxite. In Baeyer's process the powdered ore is treated with hot concentrated sodium hydroxide solution, which dissolves the amphoteric aluminium oxide as sodium aluminate while impurities such as iron(III) oxide remain undissolved and are filtered off. The filtrate is diluted and seeded with aluminium hydroxide, which precipitates and is then heated to give pure alumina.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The process depends on the amphoteric nature of aluminium oxide.
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