/ClO
Ca + H2SO4 = CaSO4 + HCl + HClO,
\Cl
HCl + HClO = H2O + 2Cl.
This reaction can be employed in the preparation of chlorine, or the nascent chlorine may be used as a bleaching agent.
2. It is slowly decomposed by the carbon dioxide of the air, yielding calcium carbonate and chlorine:
CaOCl2 + CO2 = CaCO3 + 2Cl.
Owing to this slow action the substance is a good disinfectant.
3. When its solution is boiled the substance breaks down into calcium chloride and chlorate:
6CaOCl2 = 5CaCl2 + Ca(ClO3)2.
This reaction is used in the preparation of potassium chlorate.
Calcium fluoride (fluorspar) (CaF2). Fluorspar has already been mentioned as the chief natural compound of fluorine. It is found in large quantities in a number of localities, and is often crystallized in perfect cubes of a light green or amethyst color. It can be melted easily in a furnace, and is sometimes used in the fused condition in metallurgical operations to protect a metal from the action of the air during its reduction. It is used as the chief source of fluorine compounds, especially hydrofluoric acid.