limescream cheesewhite sugar
the reaction is calcium hydroxide (lime) reacting with carbonic acid form when carbon dioxide is dissolved in water forming calcium carbonate and water. Ca(OH)2 + H2CO3 -----> CaCO3 + 2H2O
Lime water turns milky upon bubbling carbondioxide gas into it, since insoluble calcium carbonate is formed. Any excess CO2 gas appears to dissolve the calcium carbonate formed. CaO + H2O ---> Ca(OH)2 +CO2 --> CaCO3 CaCO3 + CO2 + H2O --> Ca2+ + 2HCO3 - Excess carbondioxide gas releases calcium ion from the insoluble. so the cloudiness disappears. This phenomenon is seen evidently in limestone mines, where CO2 gas in ground waters dissolving and reprecipitation of carbonate-- caving in of the mines.
