Question

Give reason for the following : The blue colour of aq. copper sulphate does not change when it is electrolysed using copper electrodes.

  • Electrolysis
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Answer

For every copper ion (Cu2+) discharged at the cathode as neutral copper atom (Cu), a copper ion (Cu2+) is added to the solution at the anode. Hence, total number of Cu2+ remains same. Therefore, the blue colour of CuSO4 which is due to the presence of Cu2+ ions does not fade [SO42- and OH1- ions are spectator ions].

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