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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: thuanthuan on January 18, 2008, 06:34:31 AM

Title: electrolysis with anode Cu
Post by: thuanthuan on January 18, 2008, 06:34:31 AM

Hi, I have a question on electrolysis ?

We electrolyze a solution of NaNO3. What would happen if anode is made of copper ?

Of course, cation and anion H+ and OH- will react with the electrodes to form neutral atoms:
2H+   + 2e  -->  H2
OH-   -->  O2 + 2 H2O  +4e

I want to ask about the reaction mechanism ?
Will Cu in anode react with O2 that has just been formed ? 2Cu + O2  -->  CuO ?
If yes, will CuO react with H+ to form cation Cu (2+) and be dissolved into the solution ?

Thanks a lot.

Title: Re: electrolysis with anode Cu
Post by: AWK on January 18, 2008, 07:04:29 AM

Yes, a simple electrolysis gives hydrogen and oxygen. You may expect also some degree of reduction of NO3- by H2.
But electrolysis of nitrates may be more complex, eg:
http://chem.lapeer.org/Chem2Docs/silver.html
http://www.freepatentsonline.com/4956057.html

Title: Re: electrolysis with anode Cu
Post by: thuanthuan on January 19, 2008, 01:30:51 AM

Thanks.
So Cu won't react with O2, is that right ?

Chemistry textbook in my country always assume that Cu would react with O2 in anode ?