Hard water stains in sinks and showers can be caused by a buildup of solid calcium carbonate. These stains can be removed by bathroom cleaners containing acids such as aqueous hydrochloric acid, which reacts with the calcium carbonate to form carbon dioxide gas, aqueous calcium chloride and liquid water. a) Write a balanced equation for this reaction

CaCO3(s) + 2HCl(aq) > CaCl2(aq) + 2CO2(g) + H2O(l)

Explanation:

CaCO3(s) + 2HCl(aq) > CaCl2(aq) + 2CO2(g) + H2O(l)

When an acid reacts with a metal carbonate a salt, carbon dioxide and water are formed. Hard water usually contain Ca^2+ in the form of Ca(HCO3)2. Minor heating causes CaCO3(calcium carbonate) to deposit on surfaces through which the hard water passes.

Calcium carbonate reacts with acids to produce a calcium salt, water and carbon dioxide: Calcium carbonate + Hydrochloric acid → Calcium chloride + Water + Carbon dioxide. The carbonate radical breaks up into carbon dioxide and oxygen; the oxygen binds with the acid's hydrogen ions to make water; and a solution of calcium chloride remains.