Bleaching powder is prepared by passing chlorine gas over slaked lime, forming calcium oxychloride. It is a yellowish white powder with a strong chlorine odor. Bleaching powder is used as an oxidizing agent and disinfectant in water treatment and swimming pools. It is also used for bleaching clothes, disinfecting garbage sites, and releasing chlorine gas when mixed with sulfuric acid. Bleaching powder decomposes slowly when exposed to carbon dioxide in air, releasing chlorine gas. It is also used for bleaching wood pulp and cotton in paper manufacturing and textiles.

1. Substances in Common
Use-2
By ADT

2. Bleaching powder
• Preparation : Bleaching powder is prepared by passing chlorine gas over
solid slaked lime.
Ca(OH)2 + Cl2 --------> Ca0Cl2 + H2O

3. Properties of bleaching powder
• Bleaching powder is a yellowish white powder with strong odour of
chlorine gas.
• Its chemical name is calcium oxychloride.
• It is an oxidizing agent in many chemical reactions.

4. Uses of bleaching powder
• It is used for disinfection of drinking water and water in the swimming pool.
• It is used for bleaching clothes.
• The road side and garbage sites are disinfected by using bleaching powder.
• Bleaching powder reacts with dil. sulphuric acid to release chlorine gas.
CaOCI2 + H2SO4 ➔ CaCO3 + Cl2
• Bleaching powder undergoes slow decomposition due to the CO2 in air and
chlorine gas is released.
CaOCl2 + CO2 --- CaCO3 + Cl2

5. • Used for bleaching wood pulp in the paper manufacturing industry.
• Used as a bleaching agent in the textile industry for bleaching cotton
and linen.

11. • What is the formula for quick lime.What does
it form when put into water.
A. CaO, CaCO3
B. CaO, Ca(OH)2
C. Ca(OH)2, CaCO3
D. None
• A compound used for whitewashing is
A. Quick lime
B. Slaked Lime
C. Blue vitriol
D. Limestone

12. • Quick lime is used in whitewashing because
A. It is cheap
B. It forms slaked lime with water which has a nice
color.
C. It forms slaked lime with water which reacts
with atmospheric carbon dioxide to form
limestone.
D. None
• Which of the following is treated with chlorine
to obtain bleaching powder
a)CaSO4
b)Ca(OH)2
c)Mg(OH)2
d)KOH

13. • Which of the following salt is used for
removing the permanent hardness of water
a)Washing soda
b)Baking soda
c)Bleaching powder
d)NaOH