Intermediate Topic 665 of 1102 Inorganic Chemistry
Bleaching Powder
Calcium hypochlorite mixture used for disinfecting and bleaching.
In-depth explanation of Bleaching Powder
Bleaching powder is a mixture whose main active component is calcium hypochlorite, Ca(OCl)2, with calcium chloride and calcium hydroxide. It is made by passing chlorine over dry slaked lime, Ca(OH)2, and it contains roughly 30 to 35 percent available chlorine. It releases chlorine when treated with acid, which also explains its smell. The hypochlorite ion is a strong oxidizing agent that bleaches coloured compounds by oxidizing them to colourless products. It is used to disinfect water and swimming pools, and to bleach cotton and paper.
Going deeper: Bleaching Powder
Key ideas: Ca(OCl)Cl, from Cl2 on slaked lime: Ca(OH)2 + Cl2 gives CaOCl2 + H2O. It releases available chlorine with dilute acid: CaOCl2 + H2SO4 gives CaSO4 + Cl2 + H2O. Good commercial powder has 35 to 38 percent available Cl. It is a mixed salt of Cl- and OCl-. Bleaching and disinfection arise from hypochlorous acid acting as oxidant. Decomposes slowly in air with CO2 and in heat to Ca chlorate and chloride.
Common mistakes and connections: Students write it as CaCl2 plus CaO2 or call it calcium chloride; it contains both Cl- and OCl- bound to a single Ca. Its action is oxidative, not reductive like SO2. Available chlorine is measured by iodometric titration with thiosulfate. Links to halogens, disproportionation, redox titration and water treatment.
Visualization of Bleaching Powder
Chlorine oxidation states: bleaching powder holds hypochlorite (+1) and chloride (-1), and acid drives them together to give Cl2 (0). The interactive lesson shows this as a live animation or chart.
Worked example and use case
Adding dilute acid to bleaching powder releases chlorine gas: CaOCl2 + 2HCl giving CaCl2 + H2O + Cl2.
Frequently asked questions about Bleaching Powder
What is Bleaching Powder?
Calcium hypochlorite mixture used for disinfecting and bleaching.
Is Bleaching Powder a beginner, intermediate or advanced topic?
Bleaching Powder is a intermediate topic in Inorganic Chemistry. It builds on the vocabulary of beginner topics in this area.
What should I learn before Bleaching Powder?
Study these earlier topics in Inorganic Chemistry first: Hydrofluoric Acid, Interhalogen Compounds, Oxoacids of Chlorine.
What comes after Bleaching Powder?
The next topics in Inorganic Chemistry are Noble Gases and Xenon Compounds.
Can I practise Bleaching Powder with quizzes?
Yes. The interactive lesson includes a self-check question on Bleaching Powder, and the Inorganic Chemistry quiz draws on every topic in this area.
Where Bleaching Powder fits in Inorganic Chemistry
Bleaching Powder is topic 50 of 113 in Inorganic Chemistry.