This is a series of reactions starting with the decomposition of calcium carbonate (CaCO3) to form calcium oxide (CaO) and carbon dioxide (CO2). The calcium oxide then reacts with water to form calcium hydroxide (Ca(OH)2), which further reacts with hydrochloric acid (HCl) to form calcium chloride (CaCl2). The calcium chloride can then react with carbon dioxide to reform calcium carbonate.