Bleaching
Powder (Short Note)
Definition
Bleaching powder is a white amorphous
powder with smell of chlorine.
Formula of
Bleaching Powder
On the basis of available percentage
of chlorine, the formula of bleaching powder was suggested by Professor Odling.
The formula is given by
Ca(OCl)Cl or CaOCl2
Preparation of
Bleaching Powder
Bleaching powder is prepared on the
large scale by Hasen Clever Process.
The plant consist of a number of iron
cylinders in which chlorine is brought in contact with slaked lime [Ca (OH)2].
Ca(OH)2 + Cl2 —-> CaOCl2 + H2O
Chemical Reactions of Bleaching Powder
1. In aqueous solution bleaching
powder liberates chlorine.
CaOCl2 + H2O —-> Ca(OH)2 + Cl2
2. It reacts with acids to set free
chlorine.
CaOCl2 + 2HCl —-> CaCl2 + H2O +
Cl2
3. It reacts with atmospheric CO2 and
moisture to give following reaction.
2CaOCl2 + CO2 + H2O —-> CaCO3 +
CaCl2 + 2HOCl
Uses of Bleaching Powder
1. It is used for sterilization of
drinking water.
2. It is used for bleaching of cotton,
linen and paper pulp.
3. It is used for the preparation of
Cl2 gas and chloroform (CHCl3).
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