So I can’t seem to figure this reaction out. I’m pretty new to chemistry and am still learning it in high school so please don’t think I’m stupid. I have reacted 2 solitons (copper sulfate) and ( calcium hypochloride / dry chlorine) and got a light blue precipitate that resembles copper carbonate. This precipitate is what I cant seem to identify. I don’t think it’s copper chlorate because the precipate is too light blue. Any answers will be helpful thank you in advance.
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1$\begingroup$ Mixing two solutions at random is generally a bad way to learn chemistry. Copper chlorate is pretty well soluble, so it would never precipitate. I'd say it is copper hydroxide or some basic salt. $\endgroup$– Ivan NeretinCommented Dec 20, 2019 at 19:54
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1$\begingroup$ It would be a mixture of calcium sulphate and basic copper salt or even copper hydroxide, as "calcium hypochlorite" is quite basic, being complex mixture of calcium chloride, hypochlorite and hydroxide.I guess similar mixture with copper sulphate is used as a classical antifungi protection of Vitis vinifera, the common grape vine. $\endgroup$– PoutnikCommented Dec 20, 2019 at 20:24
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2 Answers
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The creation reaction for copper hypochlorite per Mellor: $$ CuSO4+Ca(OCl)2 → CaSO4(s)+Cu(OCl)2 $$ However, copper hypochlorite is not stable and on standing breaks down. I believe Mellor is likely accurate on describing the reaction and products:
Reference: "A comprehensive treatise on inorganic and theoretical chemistry", Volume 2, by Joseph William Mellor, page 271. To quote:
"R. Chenevix notes the ready solubility of cupric oxide in chlorine water, and P. Grouvelle found that the soln. obtained by passing chlorine into water with cupric oxide in suspension possessed bleaching properties, and these were retained even after the soln. had been boiled for a quarter of an hour. A. J. Balard found that the distillation of P. Grouvelle's liquor furnished some hypochlorous acid and a green oxychloride, 3CuO.CuCl2.4H20, was formed in the retort. A. J. Balard prepared a soln. of cupric hypochlorite by dissolving cupric hydroxide in hypochlorous acid. It is also made by the action of cupric sulphate on calcium hypochlorite. A. J. Balard found that copper filings are partially dissolved by hypochlorous acid, the soln. after standing some time contains cupric chloride, and deposits a green pulverulent cupric oxychloride."
So, the cupric oxychloride product maybe mixed with CaSO4.
Note, Copper oxychloride, per Wikipedia, is now referred to as dicopper chloride trihydroxide with the formula Cu2(OH)3Cl (or, more informatively, I would write as Cu(OH)2Cu(OH)Cl).
[I have personally prepared dibasic magnesium hypochlorite on another forum by mixing MgSO4 with NaOCl (aq) and adding NaOH. A white precipitate of dibasic magnesium hypochlorite results (which I have collected and experimented with). It is also NOT Mg(OH)2. Link: https://www.sciencemadness.org/whisper/viewthread.php?tid=26741#pid303723 There is also the reputed compound 'copper carbonate' which actually is also always basic copper carbonate per Wikipedia https://en.wikipedia.org/wiki/Basic_copper_carbonate ].
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1$\begingroup$ Mellor's treatise is amazing but it is slightly outdated. Certainly it is not simple Cu(OH2) but far more complex solid. $\endgroup$– ACRCommented Dec 21, 2019 at 3:14
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Your precipitate has nothing mysterious. It is simply a mixture of calcium sulfate CaSO4 and copper hydroxide Cu(OH)2, made by the following reaction : $$\ce{Ca(OH)2 + CuSO4-> CaSO4(s) + Cu(OH)2(s)}$$The Ca(OH)2 is coming from the Calcium hypochlorite, because Calcium hypochlorite is a technical product containing much Ca(OH)2. CaSO4 is a white precipitate, and Cu(OH)2 is a blue precipitate, that gets dark at 100°C, because it is decomposed by the following reaction : $$\ce{Cu(OH)2 -> CuO + H2O}$$ and the copper oxide CuO is black. CaSO4 is known to be found in the mineral gypsum.
