A concentrated solution containing H+, Cu2+,OH- and CI- was electrolyzed using platinum electrodes which of...

WAEC 2001

A concentrated solution containing H+, Cu2+,OH- and CI- was electrolyzed using platinum electrodes which of the ions will be discharged at the cathode?

A. H⁺
B. Cu²⁺
C. OH^-
D. CI^-

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Correct Answer: Option B

Explanation

When using a platinum electrode, copper ions (Cu2+) are deposited at the cathode, while hydrogen ions (H+) remain in solution.

Here's what happens during the electrolysis of a copper sulfate solution using a platinum cathode:

Cathode: Copper ions are attracted to the negative cathode and are deposited as a reddish layer of pure copper
Anode: Oxygen gas is liberated
Electrolyte: The blue color of the electrolyte disappears and it becomes dilute sulfuric acid. The less reactive a metal, the more readily its ion is reduced on the electrode surface.

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