Bleaching Powder [ Bleach-Chemistry]

Bleach is a solid or liquid chemical that is used to lighten or take away the natural color of paper, textiles, and other fibers. The bleaching procedure is used in textile finishing to create white fabric, to get materials ready for additional treatments, or to get rid of discoloration that has happened in previous procedures. Because of its microbicidal qualities, bleach is also employed as a disinfectant. As bleaches, people frequently utilize chlorine, sodium hypochlorite, calcium hypochlorite, and hydrogen peroxide. Bleaching powder is basic in character. It gives calcium chloride, chlorine, and water when bleaching powder reacts with hydrochloric acid.

An inorganic compound having the formula Ca(OCl)2 is calcium hypochlorite. It is the primary component of commercial bleaching powder, chlorine powder, and chlorinated lime products, which are used to treat water and as bleaching agents. Compared to sodium hypochlorite, this chemical is more stable and has more chlorine that is readily available. Despite the yellow appearance of commercial samples, it is a white solid. Due to its slow degradation in damp air, it has a strong chlorine odor. T.C.L. powder is another name for bleaching powder. Simply put, beaching powder is a mixture of lime and chlorine.

Fresh bleaching powder often contains 33% or more chlorine. Since bleaching powder is inherently unstable, its chlorine content decreases over time. Bleaching powder needs to be stored dry and out of direct sunlight in order to prevent chlorine loss. If the bleaching powder is packaged in a bag, it must be properly closed after use.

A laboratory test can determine the amount of chlorine present in the bleaching power.

When a very small amount of diluted acid is present, the bleaching powder reacts, releasing newly formed oxygen. The bleaching powder functions as both a bleaching and an oxidizing agent as a result of the release of the nascent oxygen.

The process of making bleaching powder:

In Bachmann's plant, bleaching powder is produced in the following ways:

The complete apparatus is set up to produce bleaching powder and includes a vertical cast-iron tower with a hopper at the top, two inlets near the base (one for chlorine and the other for hot air), and an exit for waste gases towards the top. Then, this tower is equipped with shelves that are positioned with spinning rakes at various heights. There are eight shelves altogether. The hopper is filled with slaked lime. It finally makes touch with chlorine, which is steadily flowing upward. Then, at the tower's base, in the barrel region, the bleaching powder is gathered. In short, Chlorine gas, which is a byproduct of the Chlor-alkali process, reacts with dry slaked lime (Ca(OCl2)) to create bleaching powder.

Conditions to be looked after during the manufacture: 

• The chlorine used should be dilute in nature. 
• The temperature should be maintained below 40°C.

Bleaching powder's characteristics:

1. The scent of chlorine is very noticeable in bleaching powder, which is a light yellowish powder.
2. Chlorine is created by a reaction with weak acids.
3. It can be dissolved in cold water. After dilution, the lime is left as an insoluble residue.
4. The chlorine from the bleaching powder is released when it reacts with an excess of a diluted substance, like diluted sulfuric acid. As a result, the chlorine created when diluted acid reacts with bleaching powder serves as a bleaching agent. Thus, the bleaching agent in bleaching powder is chlorine.

Bleaching Powder Applications

• It is employed in the textile sector as a bleaching agent for cotton and linen as well as for the laundry's use in bleaching soiled clothing. Bleaching powder is mainly used for removing colors from materials.
• Due to its potent oxidizing properties, it is employed as an oxidizer in numerous industries.
• It is employed as a disinfectant to purify water so that it can be consumed.
• Used in the papermaking business to bleach wood pulp.

A few of bleaching powder's negative consequences include:

1. Because bleaching powder fumes are so potent, breathing them in can have a variety of negative health effects.
2. The skin is severely corroded and irritated by it.
3. It might also cause lumps to develop in the eyes.
4. Human tissue could be burned both internally and externally.