Answer: Reduction of metal oxide by heating with a reducing agent (e.g., coke/carbon).
- A Reduction of metal oxide by heating with a reducing agent (e.g., coke/carbon)
- B Direct oxidation of the raw ore prior to any reduction step under most conditions encountered
- C Simple dissolution of the ore in a strong mineral acid as frequently observed in practice
- D Electrolysis of the ore in aqueous solution in many documented cases according to conventional understanding
Correct answer: A. Reduction of metal oxide by heating with a reducing agent (e.g., coke/carbon)
Explanation: Smelting uses carbon (coke) or other reducing agents to reduce metal oxides to the metal at high temperature.
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.