Lime Water Reacts with Chlorine to Form (a) CaCl2 (b) CaOCl2 (c) Ca(ClO3)2 (d) CaO2Cl2

Answer.  (d) CaOCl2 

It is known as Calcium hypochlorite or bleaching powder. 

Lime water is a combination of a calcium element where calcium is a cation and hydroxyl is an anion. Chlorine is a group 17-element component and is a halogen and, when it reacts with lime water, the formation of calcium hypochlorite forms.