Same chapter3 marksDifficulty: Medium
Calculate the mass of copper deposited when a current of 2 A is passed through copper sulphate solution for 30 minutes. (Cu = 63.5, F = 96,500 C)
Electrochemistry
3 marksDifficulty: Medium
What is corrosion, and how does the electrochemical theory explain the rusting of iron?
Original Khojo Papers practice question — not from a past board paper.
Answer
Corrosion is the slow eating away of a metal by its surroundings. In rusting, one part of the iron surface acts as an anode where iron is oxidised to Fe2+, and another part as a cathode where oxygen and water are reduced. The Fe2+ is oxidised further by atmospheric oxygen to hydrated iron(III) oxide, which is rust.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
Galvanising and cathodic protection both work by giving the iron a more easily oxidised partner.
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