Chemistry 5070 · O Level · Electrolysis

Electrolysis — practice question

The table presents several statements about electrolysis together with the explanation for why each statement is correct. Which row contains a correct statement and the correct explanation for why it is correct?

  • AStatement: Aqueous copper(II) sulfate and aqueous copper(II) nitrate are suitable electrolytes when used to copper plate objects. Reason: Both solutions contain $\text{Cu}^{2+}(aq)$ and can transfer copper from the anode to the cathode.
  • BStatement: During the extraction of aluminium from aluminium oxide the carbon anodes have to be replaced regularly. Reason: The anodes gradually dissolve in the molten cryolite.
  • CStatement: In the electrolysis of concentrated aqueous sodium chloride and of dilute sulfuric acid the same products are formed. Reason: $\text{H}^+(aq)$ is present in both aqueous solutions.
  • DStatement: When an aqueous mixture of zinc nitrate and copper(II) sulfate is electrolysed, zinc is formed on the cathode. Reason: Zinc is more reactive than copper.

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