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🧪 Chemistry  ·  Isolation of Elements  ·  NEET & JEE

In froth flotation, collectors such as pine oil work by making the mineral particles:

Answer: water-repellent (hydrophobic).

  • A dissolve into the gangue
  • B water-repellent (hydrophobic)
  • C water-wettable (hydrophilic)
  • D fuse into a slag

Correct answer: B. water-repellent (hydrophobic)

Explanation: Collectors coat the ore particles making them hydrophobic, so they attach to air bubbles and rise with the froth while the gangue sinks.

Ellingham Diagram (simplified)T (°C)ΔG° (more negative ↑)CO + ½O₂ → CO₂ (carbon line)2Al + 1.5O₂ → Al₂O₃2Mg + O₂ → 2MgOcrossover: above this T, carbon reduces Al₂O₃

An Ellingham diagram plots ΔG° of oxide formation against temperature for different metals; whichever line is LOWER (more negative ΔG°) at a given temperature reduces the oxide of any metal whose line sits above it - the basis of carbon reduction (Fe, Zn) vs electrolytic reduction (Al, Mg, Na) decisions.

Concept context

The science of extracting metals from ores and refining them for use. Covers concentration methods, reduction techniques, refining processes, and the thermodynamic principles that govern metal extraction.

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