Lime Bleaching Powder

Preparation. Perform the experiment in a fume cupboardl) Add 10-15 ml of water to 2 g of pure slaked lime (calcium hydroxide) and stir thoroughly. Put the mixture in a small beaker cooled with ice (why is cooling needed ) and pass chlorine purified from hydrogen chloride (how can this be done ) through it during 10-20 min. Write the equation of the reaction. 

Properties. 1. Treat a part of the prepared substance with 10 ml of water and filter off the undissolved matter. Take a small amount of the solution and see how it acts on indigo and coloured fabric. Explain what you observe. 

Can carbonic acid displace hypochlorous acid from a solution of its salt Compare the values of the dissociation constants of carbonic and hypochlorous acids (see Appendix 1, Table 9). 

Add a solution of 1 iV sulphuric acid to a part of the prepared chlorinated lime solution until the reaction is acid and carefully smell the product. Write the equation of the reaction. What happens to chlorinated lime when its concentrated solution is heated  

How does the strength of the acids change in the series including hypochlorous, hypobromous, and hypoiodous acids What ions do solutions of these acids contain How do the stability and oxidizing effect of the acids change in this series Explain the observed laws. 

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Benzoquinone-l,4 di(chloro-iniine) [called Benzo-chinon-(1.4)-bis-chlorimid or p-Chinon-bis-chlor-imid in Ger], C1N CBH4 NC1 mw 175.02, N 16.01% ndls(from w) having a si aromatic odor, mp 124 -6°(dec) expl when heated rapidly above the mp readily sol in hot ale, hot AcOH, eth or benz si sol in hot w almost insol in cold w was first prepd by Krause(Ref 2) by treating an ice-cold soln of p-phenylenediamine in dil HC1 with, an excess of chlorinated lime(bleaching powder). 

State the chemical name and formula of lime, lime water, limestone, chloride of lime, bleaching powder, marble, muriatic acid, oil of vitriol, blue vitriol, ammonia, sal ammoniac, salt, soda, potash, caustic soda, quicklime, slaked lime, cream of tartar. 

Derivation Water solution of chloride of lime (bleaching powder). 

Chlorinated Lime. Bleaching powder. Improperly called chloride of lime or calcium oxychloride". A relatively unstable chlorine carrier in solid form a complex chemical compd of indefinite composition, presumably con -sisting of varying proportions of Ca(OCI), CaClj, Ca(OH)2 and HjO in its molecular structure. Maximum available chlorine content approaches 39%. Commercial products usually range between 24% and 37% of available chlorine. 

Bleaching powder CaOCl2 is considered a mixture of calcium salts of hydrochloric and hypochlorous acids. It is manufactured by the action of dry chlorine on slaked lime. Bleaching powder is white and sparingly soluble in water. 

In his papers on oxymuriate of lime (bleaching powder) Dalton assumed that it is a compound of hydrate of lime and chlorine (oxymuriatic acid), or hyperoximuriate of lime , whilst Ure" denied that it had any definite composition, supposing that the molecules of chlorine are loosely clustered round the hydrate (i.e. the slaked lime). 

This product, called chloride of lime [67560-00-3] or bleaching powder, has about 35% available chlorine. 

Applications. Because of its high lime content, the use of hemibasic calcium hypochlorite ia geaeral sanitatioa is limited. It is used primarily ia Japan and lesser developed countries as an alternative to bleaching powder. 

Bleaching Powder. This material, known siace 1798, is made by chlorination of slightly moist hydrated lime, calcium hydroxide [1305-62-0] Ca(OH)2- It has the empirical formula Ca(OCl)2 CaCl2 Ca(OH)2 2H20. Its compositioa, loag a subject of coatroversy, was estabHshed by phase studies, microscopy, and x-ray diffraction techniques (241). The initial chlorination products are monobasic calcium chloride [14031-38-4] and dibasic calcium hypochlorite [12394-14-8] ... 

H2O) made by the older chamber process and was suitable for use ia tropical climates. Ia less developed or remote areas, bleaching powder may stiU be prepared oa a small scale by generating CI2 from Ma02, NaCl, and H2SO4, and treating it with hydrated lime placed on shelves ia an absorption chamber (245). 

Bleaching powder patented by C. Tennant (CI2 4- slaked lime) following preparation of bleaching liquors from CI2 and lime solutions by T. Henry (1788)... 

Discussion. Most hypochlorites are normally obtained only in solution, but calcium hypochlorite exists in the solid form in commercial bleaching powder which consists essentially of a mixture of calcium hypochlorite Ca(OCl)2 and the basic chloride CaCl2,Ca(0H)2,H20 some free slaked lime is usually present. The active constituent is the hypochlorite, which is responsible for the bleaching action. Upon treating bleaching powder with hydrochloric acid, chlorine is liberated ... 

Sodium hypochlorite is commercially available as an alkaline solution, normally containing the equivalent of 12-14% available chlorine. However, this is so unstable that analytical testing of its strength is always necessary before use. Calcium hypochlorite (bleaching powder), stabilised by adding lime, has been used in the past but this product is no longer used in textile bleaching. 

The phenylurethane which has been obtained is mixed with three times its weight of slaked lime and cautiously distilled from a small retort. The aniline which passes over can, with a little skill, be redistilled from a small flask, but in any case it should be identified by conversion into acetanilide and by the bleaching powder reaction. 

Chlorinated lime or bleaching powder, CaOCl2, contains about 30% w/w of available chlorine. 

Calcium hypochlorite may be prepared by passing chlorine into a slurry of lime and sodium hydroxide. Alternatively, chlorine is passed into a solution of hydrated lime to produce bleaching powder, CaCl(0Cl) H20 ... 

CI2 + 60H- 5C1- CIOs + 2H2O Reaction with lime produces a calcium salt, known as bleaching powder ... 

Also, bleaching powder is made by passing CI2 gas over slaked lime ... 

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