Acid, Base & Salt

Bleaching Powder

Bleaching powder is manufactured using chlorine which is obtained as one of the product in CHLOR-ALKALI Process.

The general chemical formula of bleaching powder is CaOCl₂ and its chemical name is calcium oxychloride. Bleaching powder is also known as chloride of lime.

Production of bleaching powder:

When chlorine gas is passed over dry slaked lime [Ca(OH)₂], bleaching powder is formed.

Physical Properties of bleaching powder:

Bleaching powder is a yellowish white solid.

Bleaching powder is soluble in water.

Bleaching powder gives strong smell of chlorine.

Chemical Properties of bleaching powder:

When bleaching powder reacts with sulphuric acid, it gives calcium sulphate, chlorine and water.

When bleaching powder reacts with hydrochloric acid, it gives calcium chloride, chlorine and water.

Solution of bleaching powder is basic in character.

When bleaching powder is dissolved in water, it gives calcium hydroxide and hypochlorous acid. Instead of formation of an acid in aqueous solution, aqueous solution of bleaching powder turns red litmus paper blue. This happens because hypochlorous acid is very weak acid while calcium hydroxide is stronger base than hypochlorous acid. Thus, solution of bleaching powder shows basic character.

In bleaching powder, the word ‘bleach’ means decolouration, whiten or disinfectant. Bleaching powder is a powerful oxidizing agent, as it contains chlorine, thus because of oxidation bleaching powder acts as an decoloring agent, whitening agent and disinfectant.

Use of bleaching powder:

• Bleaching powder is used in whitening of cloth and in removing of stains.
• Bleaching powder is used as disinfectant, algae cleaner, moss remover, weed-killers, etc.
• Bleaching powder is used in purification of water as disinfectant.
• Bleaching powder is used in swimming pool water as disinfectant.
• In manufacturing of chloroform.
• Bleacing powder is used as oxidising agent in many chemical industries.
• Bleaching powder is used in bleaching of cotton in textile industries.
• Bleaching powder is used in paper industries in bleaching of wood pulp.