I was performing an experiment that my friend told me about. Basically you put a small amount of copper carbonate in hydrogen peroxide, 3%. it will
change colors from blue to dark brown. I filtered this mixture and the filtrate was green while the filtrand is brown. I repeated the experiment but
this time the filtrate was brown and again the filtrand was brown. Does anyone know what has happened here? All that I know is that it is a copper
compound because it made a solution of potassium ferrocyanide turn coppery-pink color. It was also giving off a gas that smelt like ozone.AndersHoveland - 30-8-2011 at 12:19
Elemental titanium shows good corrosion resistance against alkaline hypochlorite. Interestingly, however, alkaline solutions of hydrogen peroxide are
known to corrode titanium! It is thought that the HOO- anion forms a complex with the protective surface oxide layer, Ti(OH)2O2 (with titanium still
in the +4 oxidation state), the soluble complex later hydrolyzing into Ti(OH)4 and H2O2. chemdude118 - 30-8-2011 at 12:50
I'm sorry, I don't understand what exactly your telling me. I don't have any titanium compounds Endimion17 - 30-8-2011 at 13:12
AndersHoveland, and what does titanium(IV) have to do with his copper reaction?
In fact, peroxide indicator is titanyl (TiO<sup>2+</sup> sulphate,
because it becomes brownish red, yielding peroxotitanyl (TiO<sub>2</sub><sup>2+</sup> which has nothing to do with ligands. It's an oxycation.
chemdude118, where did you get "copper carbonate"? Could it possibly be basic carbonate, and you prepared it yourself?
I'm looking at the reaction at the moment. It doesn't turn brown at once. It goes from turqoise (basic carbonate) to more green than blue suspension,
and then slow effervescence of oxygen begins. Color slowly turns to olive green, oxygen increases slightly.chemdude118 - 30-8-2011 at 13:39
I made my own copper carbonate from sodium carbonate and copper sulfate. It did undergo the changes that you described. Can you describe what happened
to me?
ThanksEndimion17 - 30-8-2011 at 16:28
I'm looking at the test tube and apparently, there are two solids inside. An olive green and an actual green one. That's interesting. Maybe the first
one is very unstable, perhaps even a bit photosensitive? Or maybe it's just one solid which color differs because of the particle size?
I really can't tell what was that olive green solid at the begining. Maybe some kind of cuprate of copper?
Homemade basic copper carbonate is really not the stuff you want to begin with as it's too complex. Who knows what happened. The mixture looks really
weird. I bet someone did it several decades ago and now it's in an old book somewhere.
But I can tell you this. Dried and heated, it gives copper(II) oxide. It really could be some kind of cuprate.
[Edited on 31-8-2011 by Endimion17]woelen - 30-8-2011 at 23:24
It is an unstable peroxide of copper. A very simple and instructive experiment is to add a solution of copper sulfate to a solution of NaOH. This
gives a blue precipitate of Cu(OH)2. If you add some H2O2 to this, then it turns dark brown or even black. Olive green colors also are possible.
The copper carbonate, made from aqueous solution is so-called basic copper carbonate (copper hydroxide+carbonate). This shows a similar reaction. Your
olive green, brown and possible black products are a complicated mixture containing copper peroxide, carbonate and hydroxide.chemdude118 - 31-8-2011 at 05:49
When I filtered my solution, it was brown but had a turquoise colored substance in the center. Endimion17 - 31-8-2011 at 07:08
It could be piece that never got the chance to react.
Anyways, as Woelen told you, it's a complicated mixture. Try exposing it to the ultraviolet rays for a couple of minutes.chemdude118 - 31-8-2011 at 07:12
Right now its cloudy and dont have batteries for my UV light.chemdude118 - 31-8-2011 at 07:15
I mixed it with a lot of vinegar and the color changed to a bluish-green.chemdude118 - 31-8-2011 at 07:59
When you mix the copper carbonate and hydrogen peroxide, let it stand for 20 minutes. Then filter the mixture and you should get a green solution. It
is an indicator. It is yellow in acids and green in neutral or base.#maverick# - 31-8-2011 at 09:20
When you mix the copper carbonate and hydrogen peroxide, let it stand for 20 minutes. Then filter the mixture and you should get a green solution. It
is an indicator. It is yellow in acids and green in neutral or base.
that sounds interesting i will try this next time i am in lab
sulphate,
because it becomes brownish red, yielding peroxotitanyl (TiO<sub>2</sub><sup>2+</sup>
