Two separate electrolytic cells are supplied by the same direct-current power source
CHEMISTRY · Multi-part · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry
Problem
Two separate electrolytic cells are supplied by the same direct-current power source. Cell A contains CuSO4(aq) with an inert cathode on which copper is deposited. Cell B contains NiSO4(aq) with an inert cathode on which nickel is deposited.
The power supply can be wired so that the two cells operate (i) in series or (ii) in parallel. In both arrangements, the experiment runs for the same time interval with an identical applied voltage. No numerical data are provided. Answer the following qualitatively, supporting each statement with fundamental principles of electrolysis.
(a) For the series arrangement, describe the relationship between the quantity of electric charge that passes through Cell A and the quantity that passes through Cell B during the experiment.
(b) For the parallel arrangement, assume the effective electrical resistance of each cell is identical. Explain how the total current supplied by the source is distributed between the two branches.
(c) Comparing the two wiring methods, indicate which arrangement will produce the greater mass of copper on the cathode of Cell A during the fixed time interval. Justify your answer in terms of charge flow and the stoichiometry of the half-reactions.