[ching-a-ling]

Hello all.

I was doing a fun little electrolysis experiment in which two (older) pennies were put into water that was saturated in NaCl. My goal of the experiment was to produce CuO + H₂.  I have a few questions about exactly what this experiment yields and how I can revert the CuO back into pure Copper (for fun) .

When the electricity is going through the salt water and the gas is bubbling from only one of the electrodes, (I assume that the oxygen from the one copper electrode is attaching itself to a Cu molecule to make CuO. Please correct me if I am wrong.) is Cl₂ mixed in with the H₂? I smell chlorine when it is happening.

My other question is: How can I get CuO back to pure Cu without some sulfuric acid? Is there a way?

TYIA for taking the time to read and respond.

Alex

[xiankai]

the gas produced was most probably chlorine, since its more readily electrolysed than oxygen. thus u wont be having CuO.

H2 isnt produced as well, because the copper electrode is more easily electrolysed into copper ions than hydrogen is electrolysed into hydrogen gas.

did u see one of the pennies corrode? if so, that is the proof of the copper electrode being electrolysed into copper ions.

[Garneck]

xiankai is correct, you cannot obtain hydrogen on a copper electrode.. and you won't get CuO on any of those pennies.. you'll get a solution containing Cu²⁺ ions. Doesn't the colour of the electrolyte change during the electrolysis?

[ching-a-ling]

Thank you for your comments.

The water has a green/brown precipitate in it, and the pennies do corrode.  After I dry out the precipitate, it turns into a red/orange hard clayish substance.  What is this stuff?

Another thing is that when I pump electricity through the electrodes, gas collects in the bottle I am using, and when I light it it pops (combusts.)  So, there must be some flammable gas in the small chamber of the bottle.

How can I find out what the precipitate is? I tried burning it, and it just burns orange.

Thanks

Alex

[constant thinker]

I don't think you want to be smelling chlorine gas.

I read of an expirement that used magnetite (I think that's what it was) to seperate O from a couple of different metals. Sure it's probably not what your looking for but I thought it was intresting.

Can anyone elaborate on it? Or has heard about it?