Which one of the following is present as an active ingredient in bleaching powder for bleaching action?
- CaOCl2
- Ca(OCl)2
- CaO2Cl
- CaCl2
Answer
(2) Ca(OCl)2
Solution
As per NCERT, bleaching powder is obtained by the action of chlorine on dry slaked lime:
2Ca(OH)2 + 2Cl2 Ca(OCl)2 + CaCl2 + 2H2O
Its composition is Ca(OCl)2 CaCl2 Ca(OH)2 2H2O.
The bleaching action is due to the hypochlorite ion (OCl-), which releases nascent oxygen,
the active ingredient is calcium hypochlorite, Ca(OCl)2.
Answer: (2)