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Author Topic: Electrolysis products of Calcium chloride?  (Read 9529 times)

Offline valeg96

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Electrolysis products of Calcium chloride?
« on: 19/02/2014 14:51:26 »
What are the products of the electrolysis of a solution of CaCl2? I've found that at approx 1113K it's Cl2 and metallic calcium, while other sources say that at room temp it's Ca(OH)2 and HCl. What do you know?


 

Offline chiralSPO

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Re: Electrolysis products of Calcium chloride?
« Reply #1 on: 19/02/2014 19:48:21 »
Electrolysis of pure molten CaCl2 give elemental Cl2 and Ca. There is no water involved.

When the reaction occurs in room temperature water solution, it is the water that gets reduced, producing hydrogen gas. Depending on various conditions during electrolysis (temperature, pH, ion concentrations, catalysts etc.) the reaction could produce Cl2 or ClO or O2. With a high calcium concentration, it is likely that Ca(OH)2 or similar substances precipitate out and coat the cathode (H2 generating electrode).

Hope that helps.
 

Offline valeg96

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Re: Electrolysis products of Calcium chloride?
« Reply #2 on: 20/02/2014 18:33:48 »
Thanks ChiralSPO. Do you know how should i prepare the electrolysis f i wanted to produce Ca(OH)2? I have pure copper, lead and graphite electrodes, and no restrictions on CaCl2.
 

Offline chiralSPO

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Re: Electrolysis products of Calcium chloride?
« Reply #3 on: 21/02/2014 00:42:27 »
If your goal is a synthesis of Ca(OH)2, I think it would be easier to add a solution NaOH to a solution of CaCl2. If they are concentrated enough, Ca(OH)2 will precipitate out of solution, and can be recovered by filtration, centrifugation, or just waiting a long time for it to settle.

If you want to do it by electrolysis, I would say copper is the best material of those you mentioned, but stainless steel or nickel would probably be your best bet (and the surface area of a foil or sheet will be superior to that of wire). The more Ca ions are in solution, the faster the material will deposit. You should apply at least 3 V between the electrodes, and be sure there is adequate ventilation if it seems to be producing chlorine (you'll smell it!)

Be careful. Do it on a very small scale first (small volumes, small battery or power source).
 

Offline valeg96

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Re: Electrolysis products of Calcium chloride?
« Reply #4 on: 21/02/2014 17:28:31 »
thank you chiralSPO, I think i'll do 2NaOH+CaCl2->2NaCl+Ca(OH)2, but also try the electrolysis method.

Do you also know what will produce an electrolysis of a solution of FeCl2?
 

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Re: Electrolysis products of Calcium chloride?
« Reply #5 on: 21/02/2014 20:03:49 »
You would probably get metallic iron, though there might be some hydrogen production and precipitation of iron hydroxides or oxides. The "activity series" should be very helpful in answering some of these questions. Any metal that is less "active" than hydrogen can be made by electrolysis in water. Any metal that is more "active" than hydrogen cannot.

Google the term "activity series" or "reduction potential" and you should be able to find some useful information.
 

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Re: Electrolysis products of Calcium chloride?
« Reply #5 on: 21/02/2014 20:03:49 »

 

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