When calcium carbonate reacts with dilute hydrochloric acid, a gas X is formed. When gas X is passed through lime water, it turns milky due to the formation of precipitate Y. So, Y is ____.
Calcium carbonate
Calcium carbonate reacts with dilute hydrochloric acid to form calcium chloride, water and carbon dioxide gas.
CaCO3+2HCl→CaCl2+H2O+CO2
When CO2 is passed through lime water, it turns milky due to the formation of white precipitate of calcium carbonate.
Ca(OH)2+CO2→CaCO3↓+H2O