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Question
Describe what happens to the iron object and the copper rod.
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Solution
The copper anode continuously dissolves as ions in solution and is replaced periodically. The electrolyte dissociates into Cu2+ ions, which migrate towards the iron object taken as the cathode and are deposited as neutral copper atoms on the cathode.
Electrolyte: Aqueous solution of nickel sulphate
Dissociation: \[\ce{CuSO4 ⇌ Cu^2^+ + SO^2^-4}\]
\[\ce{H2O ⇌ H^+ + OH^-}\]
Electrodes:
- Cathode: Article to be electroplated
- Anode: Block of pure copper
Electrode reactions:
- Reaction at cathode: \[\ce{Cu^{2+} + 2e^- -> Cu}\] (deposited)
- Reaction at anode: \[\ce{Cu - 2e^- -> Cu^{2+}}\]
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