Why do I get varied results with Copper electrolysis?

Question

I have tried copper electrolysis several times using pennys and various batteries (1.5 v to 9 v). Sometimes I get a brownish dark green solution and other times I get a blueish green solution (what I expected). I know I am getting a Copper Chloride, but why the difference in color? The only other ingediants I use is salt.

Answer 1

1) Perhaps you are getting Cu2+ ions (blueish green) some times and Cu1+ ions (dark green) other times. It may have something to do with the difference in voltage you have between the batteries.
2) You may have some oxidation of the pennies which is entering in to the color of the solution. Copper (II) oxide (CuO) is black and will cause the solution to turn dark.

Answer 2

All the elements undergo redox at different voltages. The solution color is due to the ions dissolved in it. So unless you're using pure everything, you probably have all kinds of ions in the solution depending on the impurities and the different voltages.