How is chloride of lime chemically different from calcium chloride " Why does chloride of lime gradually lose its chlorine when kept exposed to air ?

Explanation

Chloride of lime is calcium oxy chloride `[(Ca(OCl)Cl]` also known as bleaching powser. Calcium chloride is `CaCl_(2).` Bleaching powder loses its chlorine on exposure to air because `CO_(2)` present in air reacts with it to evolve chlorine as follows :
`underset(("Bleaching powder"))underset("Chloride of lime")(CaOCl_(2)+CO_(2))tounderset(("Air"))(CaCO_(3))+Cl_(2)`