Name: Electrorefining
Uploaded: 2019-07-19
Duration: 9 min 31 s
Description: Electrorefining is a process in which materials, usually metals, are purified through an electrolytic cell. To learn more about electrorefining, let's watch...

Question

Electroplating is an important application of electrolytic cells with commercial implications. Copper may be plated using an electrolytic cell with an aqueous acidified copper(II) sulfate electrolyte. For the copper plating of tin to make jewellery, state the half-equation at each electrode.

Assume the tin electrode is inert. Suggest two observations that you would be able to make as the electroplating progresses.

Accepted Answer

Tin cathode (negative electrode): ${Cu}^{2 +} (aq) + 2 e^{-} \to Cu (s)$

copper anode (positive electrode): $Cu (s) \to {Cu}^{2 +} (aq) + 2 e^{-}$

Observations: the tin cathode changes colour from silvery to red, becomes thicker, and its mass gradually increases (due to copper deposition); the copper anode becomes thinner and its mass gradually decreases (due to copper passing into the solution); the blue colour of the solution does not change (as the amount of copper ions consumed at the cathode is equal to the amount of copper ions produced at the anode); the temperature of the solution may rise (as some electrical energy will be converted to heat due to non-zero electrical resistance of the electrolyte).

Important Questions on Redox Processes (AHL)

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