Question

Give the properties and uses of bleaching powder.

Answer 1

Let us understand what bleaching powder id. Bleaching powder is a pale yellowish powder and has a strong smell. Its chemical formula is $CaOCl_2$ and its chemical name is calcium hypochlorite. It is also known as chloride of lime.

Complete step by step answer:
We have to remember that the bleaching powder is synthesized by the action of chlorine gas (produced from the chlor-alkali process) on dry slaked lime with the liberation of calcium chloride and water as a byproduct. We can write the chemical equation for this reaction as,
$2Ca{\left( {OH} \right)_2} + C{l_2} \to Ca{\left( {OCl} \right)_2} + {H_2}O$
Now we can discuss about the properties as,
Appearance is pale yellow in colour.
It has a strong smell of chlorine
It is soluble in water but it does not form a clear homogeneous solution due to the presence of impurities. Hence a clear solution is not observed
On standing for a longer time, it undergoes auto-oxidation due to which bleaching action decreases.
Now we can discuss about the uses as,
It is used for bleaching cotton and linen in the textile industry, for bleaching wood pulp in the paper industry and for bleaching washed clothes in laundry.
It is also used as a disinfectant for water to make it germ free and potable.
It is used as an oxidizing agent in many chemical industries.
It is used for the manufacture of chloroform.

Note: We must remember that the bleaching powder is a pale yellowish powder that decomposes on contact with water and has the characteristic odour of gaseous chlorine: regarded, when dry, as a mixed calcium hypochlorite-chloride, used as a commercial bleach for wood pulp, textiles, oils, and soaps, and in laundering as a decolorizer and disinfectant.