Which of the following is not the use of bleaching powder?
(i) to make drinking water free from germs
(ii) in soda-acid fire extinguishers
(iii) as an oxidising agent in many chemical industries
(iv) for baking cakes

Correct option is C

The correct answer is (C) iv.

• Bleaching powder is not used for baking cakes. Baking requires agents like baking powder or baking soda, not bleaching powder, which is a chemical compound with germicidal and oxidizing properties.

Explanation of other options:

1. To make drinking water free from germs : Bleaching powder is used as a disinfectant for purifying drinking water by releasing chlorine, which kills harmful microorganisms.
2. In soda-acid fire extinguishers : This is incorrect; bleaching powder is not used in fire extinguishers. Soda-acid fire extinguishers typically use a combination of sodium bicarbonate and acid.
3. As an oxidizing agent in many chemical industries : Bleaching powder acts as an oxidizing agent in various chemical processes, such as bleaching textiles and paper.

Key Point:

• Bleaching powder (CaOCl₂) is used mainly as a disinfectant, bleaching agent, and oxidizer, but it is unsuitable for baking or consumption.