Which metal is known for forming a thin, adherent oxide layer that protects it from further corrosion, and is therefore widely used to make stainless steel?
Answer
C. Chromium
Step-by-step solution
- Stainless steel relies on a protective passive film that prevents further oxidation.
- The metal that forms a stable, adherent Cr₂O₃ layer is chromium.
- Among the options, only chromium exhibits this specific passivation behavior used in stainless steel.
- Hence option C is correct.
Common mistake: Choosing aluminium or zinc, which also oxidise but do not give stainless‑steel properties
Concept tested: Passivation of metals
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