hi everyone, can I get some input on this question?Aqueous solutions of Cu(+2) ion are blue - the hight the concentration, the darker the color. When a strip of copper metal is immersed in a solution of Cu(+2), the color stays the same. Why does this happen?
The Cu+2 is what is blue. The only way to reduce the color is to add electrons to the Cu+2 to make it Cu(0). If you place elemental Cu in the solution, the only thing that could possibly happen would be for the Cu(0) to donate electrons to the Cu+2, but then the Cu(0) would become Cu+2. No net change. If you put a reducing agent in the solution, then the color would disappear as the Cu+2 got reduced to Cu(0).
That's because, Cu (2+) ions are responsible for the blue colour. The solution's oxidation state is 2. This oxidation state is necessary for the blue colour of the solution. Copper metal's oxidation state is 0 (Zero) and the copper doesn't dissolve in its solution. Hence there occurs no colour change. :)
