Answer: its own oxide line lies below that of the other metal.
- A its own oxide line lies above that of the other metal
- B its own oxide line lies below that of the other metal
- C it has a higher melting point than the other metal
- D it is far more abundant in nature than the other one
Correct answer: B. its own oxide line lies below that of the other metal
Explanation: A metal whose oxide-formation line lies lower (more negative ΔG) has a greater affinity for oxygen, so it can reduce the oxide of the metal whose line lies above it.
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.