This document discusses how to prepare a 0.1% active chlorine solution from commercial bleaching powder. It explains that bleaching powder is composed of calcium hypochlorite (Ca(ClO)2) and calcium chloride hypochlorite (Ca(ClO)Cl) with a total chlorine content of around 50-27%. To make a 0.1% solution, 3 grams of bleaching powder should be dissolved in 1000mL of water, producing a 3000ppm solution, or 0.1% active chlorine. Alternative methods are provided if a weighing scale is not available.

1. How to prepare 0.1% Active Chlorine
Lets discuss ‘Bleaching powder as a
Sanitizer and some chemistry’
SHREE MALLIKARJUN
&
Shri Chetan Manju Desai College
Canacona Goa

2. Bleaching powder and its solution is toxic
-Refer to MSDS of hypochlorite
-Less than 4 ppm is usually present
in drinking water supply

3. Bleaching powder (SOLID)
Calcium hypochlorite -Ca(ClO)2
𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 = 142.91 g
Active Chlorine % =
𝐴𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑎𝑐𝑡𝑖𝑣𝑒 𝑐ℎ𝑙𝑜𝑟𝑖𝑛𝑒
𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓Ca(ClO)2
× 100
=
2×(35.45)
142.91
× 100
= 49.61 %
Calcium chloride hypochlorite Ca(ClO)Cl
𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 =126.91 g
Active Chlorine % =
𝐴𝑚𝑜𝑢𝑛𝑡 𝑜𝑓 𝑎𝑐𝑡𝑖𝑣𝑒 𝑐ℎ𝑙𝑜𝑟𝑖𝑛𝑒
𝑀𝑜𝑙𝑒𝑐𝑢𝑙𝑎𝑟 𝑤𝑒𝑖𝑔ℎ𝑡 𝑜𝑓Ca(ClO)Cl
× 100
=
1× (35.45)
126.91
× 100
= 27.93 %

4. Bleaching powder = Calcium
hypochlorite Ca(ClO)2 + Calcium
chloride hypochlorite Ca(ClO)Cl
% of Chlorine
50 - 27 %
Theoretically!

5. 0.1 % Active Chlorine solution from
commercial beaching powder
If 100 g of bleaching powder has 33% active chlorine
100 g in 100 mL water give 33 % active chlorine
100 g in 100 mL will give ~30 %
30 g in 100 mL will give 10 %
30 g in 1000 mL will give 1 %
30 g in 10 L will give 0.1 % solution
3 g in 1000 mL
3000 mg in 1000 mL (1 mg in 1000 mL -1 ppm)
3000 ppm solution

6. No weighing scale?
30%
70%

7. Liquid bleaching solution
• Solution of hypochlorite
Sodium hypochlorite – NaClO
74.44 g – 35.45 g
% 5 by weight = 5 g in 100 mL
= 2.38 g in 5 g
= ~2.4% in 100 mL
100 mL diluted to 1000 mL 0.24%
100 mL dilute to 2 L ~0.12%