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🧪 Chemistry  ·  Isolation of Elements  ·  NEET & JEE

What is the distribution ratio (D) in solvent extraction and why is it important?

Answer: D = [metal in organic phase]/[metal in aqueous phase]; high D means efficient extraction in fewer stages.

  • A D = [metal in organic phase]/[metal in aqueous phase]; high D means efficient extraction in fewer stages
  • B D generally represents the relative density ratio measured between the two immiscible liquid phases
  • C D supposedly indicates mainly the absolute solubility of the metal salt dissolved in plain water as frequently described
  • D D is supposedly just a numerical measure of the temperature difference between the two phases in most textbook accounts

Correct answer: A. D = [metal in organic phase]/[metal in aqueous phase]; high D means efficient extraction in fewer stages

Explanation: A high D means most of the metal partitions into the organic solvent, allowing efficient separation from other metals that have different D values; it determines the number of extraction stages needed.

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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