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Question
Explain by writing a word equation.
Limestone powder disappears on adding to dilute hydrochloric acids.
Solution
Limestone is predominantly Calcium carbonate(CaCO3). When calcium carbonate reacts with a 10% solution of HCl. Then Calcium chloride is formed as a salt along with water and carbon dioxide gas (brisk effervescence).
2HCl + CaCO3 → CaCl2 + CO2 +H2O
In this reaction, we add hydrogen ions (H+), which will react with the carbonate ion [\ce{(CO^{2-}_3)}\] to form hydrogen carbonate \[\ce{(HCO^-_3)}\] ions, which are soluble in water and the limestone will dissolve.
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