Question

(a) Write two uses of Bleaching Powder
(b) What is corrosion? Write two methods for its prevention.
(c) Write one use of Plaster of Paris.

Hint:

To prevent corrosion, you can either physically block moisture and air from reaching the metal or use a sacrificial metal like zinc, which corrodes instead of the metal you are trying to protect.

Answer 1

(a) Two Uses of Bleaching Powder:
1. Disinfection: Bleaching powder is used to disinfect drinking water, killing bacteria and other microorganisms. It is commonly used in water treatment plants.
2. Bleaching Agent: It is used in the textile and paper industries as a bleaching agent for clothes and papers.
(b) Corrosion and Methods for its Prevention:
- Corrosion: Corrosion is the gradual destruction of materials, usually metals, by chemical reactions with environmental factors such as air, water, or chemicals. An example of corrosion is the rusting of iron.
- Two Methods to Prevent Corrosion: 1. Galvanization: This is the process of coating the metal (usually iron or steel) with a layer of zinc to prevent rusting. The zinc layer prevents exposure to air and moisture. 2. Oil or Paint Coating: Applying a protective layer of oil, paint, or lacquer prevents direct contact of the metal with water and air, thus preventing corrosion.
(c) One Use of Plaster of Paris:
Plaster of Paris is commonly used in the medical field for making casts for broken bones. It is also used for making molds in art and sculpture.
Conclusion:
1. Bleaching powder is useful in disinfection and bleaching.
2. Corrosion is the degradation of metals, and it can be prevented through methods like galvanization and coating.
3. Plaster of Paris is used in making medical casts and molds.