August 24, 2019, 06:29:59 PM
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Topic: Electrolyisis with saltwater and aluminum cathode  (Read 2134 times)

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Offline Edaw

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Electrolyisis with saltwater and aluminum cathode
« on: July 06, 2018, 12:25:14 AM »
So I'm doing an electrolysis experiment and I'm using table salt, distilled water, and aluminum as my anode. After putting a current through it I see the bubbles start to form. I know that I'm producing Hydrogen and Chlorine gas, and in the sollution I believe I'm creating Sodium Hydroxides and other Aluminum Hydroxides? I really don't know, my water has turned very cloudy and yellow and I don't know what it could be. Does anyone know what it could be?

Offline chenbeier

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Re: Electrolyisis with saltwater and aluminum cathode
« Reply #1 on: July 06, 2018, 05:02:49 AM »
Aluminium reacts with the chloride to Aluminiumchloride and also hydroxides. It can be cloudy but yellow is a strange colour, maybe you have lao iron present or your table salt contain iodide.

Offline Enthalpy

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Re: Electrolyisis with saltwater and aluminum cathode
« Reply #2 on: July 06, 2018, 07:49:56 AM »
Bad choice of electrode (what is the other one?), so the result can be anything.

Did you separate the chlorine from the solution? If not, you obtained sodium hypochlorite, which can be yellow depending on the concentration.

"Aluminium" is almost always an alloy. Even aluminium paper to wrap food is allied with around 0.5% of other metals like Fe
https://www.cometmetals.com/user/metals/10767-pdfs-1-file.pdf
and very little salt can colour water.

Offline Edaw

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Re: Electrolyisis with saltwater and aluminum cathode
« Reply #3 on: July 06, 2018, 02:49:03 PM »
I used a stainless steel cathode, I didn't see any tarnishing or anything like that on it though. I also think the yellow color could have come from some copper which was attached to the aluminum anode, I accidentally I a bit of it in the water.

Offline Uber-Dan

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Re: Electrolyisis with saltwater and aluminum cathode
« Reply #4 on: July 31, 2019, 08:16:23 AM »
Hello,
I am doing a school assignment based on this experiment, and I was wondering what the specfic reaction was that occurred to the aluminium. From my understanding, correct me if I’m wrong, the aluminium is dissolved at the anode and is transported to the cathode where it is deposited and becomes aluminium oxide. I can’t find much information on this specific reaction and transportation so it would be greatly appreciated if someone could detail the relations taking place for me.
Thanks, Dan

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