You can make copper (ii) chloride from HCl, H2O2, and copper with little if any chlorine gas formation, as long as you only add a very small amount of
H2O2 initially. Cl2 can combine with Cl- to form Cl3-, much like iodine and bromine can. As the metal chloride level increases, the solution is able
to dissolve much more chlorine this way, and you can add higher levels of peroxide accordingly.
Interestingly, the solution gradually takes on a mild, slightly pleasant smell, which are not words that are normally associated with compounds
composed of chlorine, oxygen, and hydrogen. My only theory is that copper and nickel (which does the same thing) can catalyze the formation of
chloric or perchloric acid, which imparts the smell. In that case, those species would have to be removed or decomposed in order to not have them
oxidize your copper (I) salt. |