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Topic: Electrolysis of potassium iodide  (Read 787 times)

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Offline bear_007

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Electrolysis of potassium iodide
« on: August 03, 2020, 11:55:02 AM »
Iodine gas forms at Anode but hydroxyl ion is more reactive in the electrochemical series so it should electrolyse and for, oxygen, I assume if that is what is formed by hydroxyl ion, correct me if I am wrong.

Why iodine and not oxygen?

Offline Borek

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Re: Electrolysis of potassium iodide
« Reply #1 on: August 03, 2020, 06:22:13 PM »
Most often it is kinetics, oxygen is notoriously slow and requires overpotential to react faster.
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Offline bear_007

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Re: Electrolysis of potassium iodide
« Reply #2 on: August 06, 2020, 01:42:34 PM »
thanks

Offline Enthalpy

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Re: Electrolysis of potassium iodide
« Reply #3 on: August 06, 2020, 02:47:54 PM »
I don't quite grasp the "more reactive" argument.

The electrolyte contains mainly K+ and I-. These are the ions attracted by the electrodes. H+ and OH- are rare in a neutral solution.

At the electrodes, other compounds can evolve if the neutralised ions decompose water or combine in some other way. For instance K doesn't remain metallic in water, so you can obtain hydrogen and keep K+. But with iodine? I could at most imagine the formation of a hypoiodide. I don't imagine iodine in water forming something like HI and O2. Or did I get it wrongly?

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