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BLEACHING
POWDER
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| Chemical
name : Calcium chloro hypo chloride. Commercial name : Bleaching powder. Chemical formula : Ca(OCl)Cl.H2O or CaOCl2.H2O. |
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| It is a dirty white amorphous powder with pungent smell of chlorine gas. | |||
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Industrial
Preparation
of Bleaching Powder |
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| On industrial scale it is prepared by "Hasen-Clever Method". | |||
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Raw
Material
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1. Slaked
lime Ca(OH)2 |
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Hasen-Clever
Plant
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| The plant consists of four cylinder of cast-iron. Each cylinder is about 2 to 3m long .Each cylinder is provided with a stirrer to ensure the mixing of substances. There is an inlet in the upper most cylinder for Ca(OH)2. The bottom cylinder has an inlet for Cl2 and outlet for bleaching powder. Each cylinder is connected to the other by means of pipes. | |||
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Procedure
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| Slaked lime is introduced in the first cylinder with the help of compressed air .Cl2 gas is introduced from the lower most cylinder .In this way these two substances meet, when proper saturation is reached, the product is separated from the last cylinder as bleaching powder. | |||
| Ca(OH)2 + Cl2 è Ca(OCl)Cl.H2O | |||
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Properties
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| It is a strong bleaching agent. Due to liberation of chlorine gas in aqueous solution it decolorize different fabrics. It is also an antiseptic. | |||
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| Reaction
with water: Ca(OC)Cl + H2O è Ca(OH)2 + Cl2 With HCl: Ca(OCl)Cl + 2HCl è CaCl2 + Cl2 + H2O With CO2: 2Ca(OCl)Cl + CO2 + H2O è CaCO3 + CaCl2 +2HOCl |
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Uses
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| As oxidizing and bleaching agent it is used in textile and other industries. It is also used in the purification of drinking water. | |||
| Q:
How would convert magnesite in to Mg(OH)2 ? Ans: Chemically magnesite is magnesium carbonate (MgCO3). First magnesite is heated, on heating it decomposes to MgO. MgCO3 è MgO + CO2 MgO is heated with carbon and chlorine to produce MgCl2. MgO + Cl2 + C è MgCl2 + CO Finally MgCl2 is treated with Ca(OH)2 to produce Mg(OH)2. MgCl2 + Ca(OH)2 è Mg(OH)2 + CaCl2 |
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