Zaymiey

🧪 Chemistry  ·  Isolation of Elements  ·  NEET & JEE

A major limitation of the Ellingham diagram is that:

Answer: it gives no information about the rate of the reduction.

  • A it can be applied only to the noble metals like gold
  • B it is valid only at temperatures below 500 degrees
  • C it predicts the exact percentage yield of the product
  • D it gives no information about the rate of the reduction

Correct answer: D. it gives no information about the rate of the reduction

Explanation: The Ellingham diagram is purely thermodynamic (based on ΔG); it shows whether a reduction is feasible but says nothing about its kinetics or rate.

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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