Question
A student is carrying out electrolysis on copper sulfate solution. Explain why one of the electrodes is covered in a bronze deposit.
Answer
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Ava
Master · Tutor for 5 years
Answer
The bronze deposit you see on one of the electrodes is actually copper. After the electrolysis, the copper ions are reduced back to elemental copper on the cathode, resulting in the deposition of copper "bronze deposit" on it. This occurs because copper is more likely to remain in its elemental form rather than existing as a cation in the solution. It forms a deposit or plating on one electrode.
Explanation
The question is asking us why a copper electrode becomes covered in bronze during the electrolysis of copper sulfate. During the process of electrolysis, chemical changes occur when an electric current is passed through a solution. With the copper sulfate solution, there are copper (II) and sulfate ions in the solution.When carrying out the Electrolysis on copper sulfate, at the anode (the positive electrode) copper atoms being oxidized to copper ions Cu -> Cu²⁺ + 2e¯, i.e., Copper loses electrons and form cation Cu²+. At the cathode (the negative electrode), copper ions being reduced takes electrons and transform back into copper atoms Cu²⁺ + 2e¯ -> Cu. This implies that Copper (II) is being (reduc) attracted to the cathode i.e., the copper ions obtained from the anode are reduced(create charge) at the cathode (gain electrons) and plated onto the copper cathode.So, the bronze deposit on one of the electrodes is due to the plating or deposition of the copper ions on the Cathode (negative electrode). This occurs because copper is higher up in the reactivity or electrochemical series meaning it is more likely to be reduced(more likely to gain electrons) or stays in the elemental form rather than sit in the solution being a cation.This confirms facination that when electricity passes, the copper from the anode is dissoluted into the solution and the same/that copper from the solution(ref this works till the solution of CUSO4 becomes lesser) gets deposite.avers on the cathode; hence possibility of anode thinning and cathode thickening.