electrolytic solution

[TATER]

Hello, i just electrolised a solution of water and salt using a copper anode and electrode. after i had electrolised that solution, i added phenolphthalein, it turned purple, turned orange after ten minutes or so, then turned clear. does any body know what this final solution is? thanks

[woelen]

The purple color is due to formation of hydroxide at the cathode. The orange color probably is due to formation of hydrous copper (I) oxide, which is formed in a secondary reaction between material from the anode and the hydroxide from the cathode. The turning clear is not easily explained, unless the orange material precipitated. Is there any solid material at the bottom?

[TATER]

just a little bit of leftover phenolphthalein

[TATER]

i tried it again but this time i used both copper anodes. i used a test tube to capture the hydrogen produced and a strange blue residue appeared on the wall of the test tube:confused: i had also added salt to this mixture but i used no phenolphthalein.

[woelen]

The blue residue is a copper(II) compound. Most likely it is copper hydroxide, or some copper hydroxochloride. It can best be represented as [math]CuCl_{2-x}(OH)_x[/math], where x can be anything between 1 and 2.