Assertion: Chemical formula of Bleaching powder is CaOCl2.
Reason: Calcium oxide reacts with chlorine to form bleaching powder.

Dear student

Bleaching powder is Calcium Oxychloride (CaOCl₂)

The common name of calcium Oxychloride is bleaching powder and its chemical formula is CaOCl₂. It is prepared by the action of chlorine gas on dry slaked lime [Ca(OH)₂]. Hence, the raw material required for the preparation of bleaching powder are chlorine gas and dry slaked lime. 

Following is the equation for preparation of the compound

Ca(OH)₂ + Cl₂ → CaOCl₂ + H₂O
Calcium hydro-oxide reacts with chlorine to form bleaching powder not calcium-oxide.
Hence Option C is correct.
Hope it is clear
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