Question 9

The simplified diagram below represents an electrochemical cell used in the refining of copper. One of the electrodes consists of impure copper.

9.1 What type of power source, AC or DC, is used to drive the reaction in this cell? (1)

9.2 When an electric current passes through the CuCl2(aq), the mass of electrode P increases. Is electrode P the CATHODE or the ANODE?
Write down the relevant half-reaction to support the answer. (3)

9.3 The impure copper contains zinc impurities which are oxidised to zinc ions. Refer to the relative strengths of oxidising agents to explain why zinc ions will not influence the quality of the pure copper produced in this cell. (3)

9.4 Electrodes P and Q are now replaced by carbon electrodes.

9.4.1 What will be observed at electrode Q? (1)

9.4.2 How will the concentration of the electrolyte change as the reaction proceeds? Choose from INCREASES, DECREASES or REMAINS THE SAME. (1)


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