Bleaching Powder

Calcium hypochlorite is a chemical compound with formula Ca(ClO)2. It is widely used for water treatment and as a bleaching agent. This chemical is considered to be relatively stable and has greater available chlorine than sodium hypochlorite (liquid bleach).

Preparation

It is manufactured by the calcium process:
~\mathrm{2Cl_2 + 2Ca(OH)_2\longrightarrow \ Ca(OCl)_2 + CaCl_2 + 2H_2O}.
"Bleaching powder" is a mixture of calcium hypochlorite (Ca(OCl)2) and the basic chloride CaCl2, H2O with some slaked lime, Ca(OH)2.
Properties

Calcium hypochlorite is a yellow white solid which has a strong smell of chlorine. It is not highly soluble in water and is more preferably used in soft to medium-hard water. It has two forms: dry and hydrated. The hydrated form is safer to handle.
Calcium hypochlorite reacts with carbon dioxide to form calcium carbonate and release dichlorine monoxide:
~\mathrm{Ca(ClO)_2 + CO_2\longrightarrow \ CaCO_3 + Cl_2O \uparrow}.
A calcium hypochlorite solution is basic. This is due to the hydrolysis performed by the hypochlorite ion, as hypochlorous acid is weak, but calcium hydroxide is a strong base. As a result, the hypochlorite ion is a strong conjugate base, and the calcium ion is a weak conjugate acid:
ClO−
+ H2O → HClO + OH−
Similarly, calcium hypochlorite reacts with hydrochloric acid to form calcium chloride, water and gaseous chlorine:
Ca(OCl)2 + 4 HCl → CaCl2 + 2 H2O + 2 Cl2
Uses[edit]

Calcium hypochlorite is used for the disinfection of drinking water or swimming pool water. It is used as a sanitizer in outdoor swimming pools in combination with a cyanuric acid stabilizer, which reduces the loss of chlorine due to ultraviolet radiation. The calcium content hardens the water and tends to clog up some filters; hence, some products containing calcium hypochlorite also contain anti-scaling agents.
Calcium hypochlorite is an ingredient in bleaching powder, used for bleaching cotton and linen. It is used in bathroom