alleryRusting of iron requires which two chemicals in contact with the metal?
AOxygen and hydrogen only
BChlorine and nitrogen
CWater and oxygen
DOnly nitrogen from air
Answer & Solution
Correct answer: C. Water and oxygen
1. Corrosion is an electrochemical process.
2. Rusting occurs when iron is exposed to moisture (H₂O) and oxygen (O₂).
3. Iron acts as anode: Fe → Fe²⁺ + 2e⁻.
4. Oxygen at cathode: O₂ + 4H⁺ + 4e⁻ → 2H₂O; overall product is hydrated Fe₂O₃ (rust).
_Source: syllabus Chemistry, Unit 3 "Electrochemistry", §3.8_
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