Calcium carbonate can be dissolved by ammonium salts. But Ca ions accumulate and slow down the reaction. To increase the effiency it is necessary to increase ammonium ions concentration. What if use several ammonium salts together? I thought they together could make higher ammonium ions concentration than if used alone.
Ammonium acetate has good solubility similar to ammonium nitrate. The mixture of both could give higher ammonium content than these individual salts. So, I added some ammonium acetate to the solution.
The effect was astonishing. CaCO3 dissolved much more faster. By the way, the cup corroded making the solution brown. What happened?
At first, ammonium acetate decomposes. Ammonia gas escapes and acetic acid stays. Then acetic acid dissolves CaCO3.
Secondly, acetate ion is chelating agent. It makes complexes with Ca ions. Ca ions are blocked and do not suppress the reaction of dissolving CaCO3.
But if ammonium acetate accelerates the dissolution of CaCO3 it might slow the precipitation of gypsum. I checked and it is so.
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