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Reliably producing copper chloride through electrolysis.. Is this possible?


brads3290

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Hey again guys, wondering if you can answer a couple of questions :)

 

A while ago when I was playing around with electrolysis I dried out the anode (I think it was the anode) to find a green coating on it, which I suspected to be copper chloride, as I had added salt to the solution. I did a burn test on it, and sure enough the flame burned blue/green. However, since then I have not been able to produce copper chloride very well; it just seems to sometimes appear and sometimes not (and yeah, I am adding salt and using copper electrodes).

 

When electrolysing water I also tend to get a blue precipitate (I believe it to be copper hydroxide - it displays many properties of it). A couple of days ago I had an idea to collect the copper hydroxide, which I did, and then mix it in a salt water solution and electrolyse that. My idea was that the electrolysis would break the bonds of the copper/hydroxide and the sodium/choride (and hydrogen/hydroxide from the water) and I would end up with sodium hydroxide and copper chloride (copper chloride being my goal). I wasn't too sure what would happen to the spare hydroxide from the water; hydrogen would bubble, and I thought the hydroxide ions might form more copper hydroxide with the copper ions in the water.

 

It worked in theory, but in actual fact I got a green/brown sludge that wasn't interesting at all.. and most importantly, it didn't burn green :(

Can anyone think of where I went wrong?

 

Also, does anyone know why copper hydroxide doesn't burn green, and neither does copper oxide? This Wikipedia article seems to think they should:

 

 

In a flame test, copper chlorides, like all copper compounds, emit green-blue.

So apparently all copper compounds should burn blue/green.. The ones I got didn't, which is odd I thought.

 

Any help would be much appreciated :)

Edited by brads3290
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CuCl2 + 2NaOH → Cu(OH)2 + 2NaCl

If you want CuCl2 do reaction:

Cu(OH)2 + 2HCl → CuCl2 + 2H2O

 

Also, does anyone know why copper hydroxide doesn't burn green, and neither does copper oxide?

 

While heating Cu(OH)2 will be converting to black dust CuO and H2O

I just took CuO, and put in methane gas burner, and it's indeed green.
With hand lighter it did not work though.

Edited by Sensei
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I've heard that copper chloride is really soluble in water.. I presume that the reaction you specified would result in a solution; is there any way to remove the water and have copper chloride in a solid (probably powder) form? I've had it on my copper electrodes before, I think, so it must be possible to solidify somehow. Could I boil the water out maybe?

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