Cuprous Chloride(WSDTY) is dissolved by using Nitric Acid. Copper is oxidized in this process but rather than forming Hydrogen as the reduction product, Nitric Acid is reduced to NO2 gas. To understand this, review the EMF (electromotive force) Table or Activity Series. This also explains why HCl doesn't react directly with Cu metal to form the chloride.

Once in solution, the copper is first precipitated as the insoluble carbonate and only after that, converted to Cupric Chloride by adding HCl. Cu(NO3)2 + Na2CO3 ----> CuCO3 + 2 NaNO3 and CuCO3 + 2 HCl ----> CuCl2 + CO2 + H2O

The direct addition of strong HCl to Copper dissolved in nitric acid will give rise to the following balanced reaction. 2 H+ + 2 Cl- + 2 HNO3 ----> Cl2 + 2 NO2 + 2 H2O. Both the Chlorine and the Nitrogen Dioxide generated are very toxic.

Adding water to the Cuprous Chloro complex results in a precipitation of CuCl. To explain this, remember, solid CuCl dissolves to form the soluble cuprous chloro complex at high concentrations of Chloride ion . CuCl(solid)-----> CuCl(solution) + 2 Cl- -----> CuCl32-

However, this is an equilibrium. Adding water produces the expected result based on this equilibrium. The added water dilutes the solution, decreasing the Chloride ion concentration. The Principle of LeChatelier predicts that dilution of the chloride ion, favors the formation of CuCl. Finally the precipitation of the CuCl enhances the reaction by removing the CuCl from the equilibrium.

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