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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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RELATED QUESTIONS
Name the metallic ions that should be present in the electrolyte when an article made of copper is to be electroplated with silver.
State one relevant observation for the following:
At the anode when aqueous copper sulphate solution is electrolysed using copper electrodes.
Out of Cu and Ag, which is more active?
Give reason for the following:
The blue colour of aqueous copper sulphate fades when it is electrolysed using platinum electrodes.
Give reason for the following:
For electroplating with silver, silver nitrate is not used as an electrolyte.
The following questions are about electroplating of copper wire with silver.
(a) What ions must be present in the electrolyte?
(b) Of what substance must the anode be made up of?
(c) What will the cathode be made up of?
(d) Write the equation for the reaction which takes place at the cathode.
What ions must be present in a solution used for electroplating a particular metal?
A solution of silver nitrate is a good electrolyte but is not used for electroplating an article with silver.
Which solution is preferred as electrolyte, CuSO4 or FeSO4?
Write two applications of electrolysis in which the anode diminishes in mass.
