Answer: Contains more carbon (2-4% C) and is more brittle; steel has 0.1-1.5% C.
- A Contains more carbon (2-4% C) and is more brittle; steel has 0.1-1.5% C
- B Actually contains less carbon than steel does
- C Is a noticeably purer form of iron than steel
- D Is always used directly in construction without any further conversion
Correct answer: A. Contains more carbon (2-4% C) and is more brittle; steel has 0.1-1.5% C
Explanation: Pig iron from the blast furnace has 2-4% carbon and other impurities; it is brittle. Steel is pig iron with carbon reduced and controlled (0.1-1.5%) for strength and ductility.
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.