Bleaching-powder sentence example
Balard discovered chlorine monoxide in 1834, investigating its properties and reactions; and his observations on hypochlorous acid and hypochlorites led him to conclude that " bleaching-powder " or " chloride of lime " was a compound or mixture in equimolecular proportions of calcium chloride and hypochlorite, with a little calcium hydrate.
The metallic film is tested with 20% nitric acid and with bleaching-powder solution.
Arsenic is insoluble in the acid, but immediately dissolves in the bleaching-powder.
The black films of antimony and bismuth and the grey mottled film of mercury are slowly soluble in the acid, and untouched by bleaching-powder.
The black films of tin, lead and cadmium dissolve at once in the acid, the lead film being also soluble in bleaching-powder.Advertisement
Lead dioxide, Pb0 2, also known as "puce oxide," occurs in nature as the mineral plattnerite, and may be most conveniently prepared by heating mixed solutions of lead acetate and bleaching powder until the original precipitate blackens.
There have also been introduced processes in which the chlorine is generated in the chloridizing vat, the reagents used being dilute solutions of bleaching powder and an acid.
There are three substances which can be relied on more or less to remove this compound, and the gas to be purified may be passed either through acid copper salts, through bleaching powder or through chromic acid.
Lunge, who recommends the use of bleaching powder.
Dr Wolff employs purifiers in which the gas is washed with water containing calcium chloride, and then passed through bleaching-powder solution or other oxidizing material.Advertisement
The substances used as tests in these reactions are caustic potash and calcium hypochlorite; the former being the substance dissolved in an equal weight of water and the latter a saturated extract of bleaching powder in water.
In the preparation of chloroform by the action of bleaching powder on ethyl alcohol it is probable that the alcohol is ..rst oxidized to acetaldehyde, which is subsequently chlorinated and then decomposed.
In the Carboniferous Limestone series, the purer kinds of limestone are used for the manufacture of lime, bleaching powder and similar products, also as a flux in the smelting of iron; some of the less pure varieties are used in making cement.
In his researches on the bleaching compounds of chlorine he was the first to advance the view that bleaching-powder is a double compound of calcium chloride and hypochlorite; and he devoted much time to the problem of economically obtaining soda and potash from seawater, though here his efforts were nullified by the discovery of the much richer sources of supply afforded by the Stassfurt deposits.
Where (as is the more usual case) the chlorine has to serve for the manufacture of bleaching-powder, it must first be deprived of the great amount of moisture which it contains, by means of coke-towers fed with moderately strong sulphuric acid.Advertisement
But most of the chlorine is utilized for the production of bleaching-powder, of bleach-liquor, and of chlorate of potash.
Bleaching-powder is a compound obtained by the action of free chlorine on hydrated lime, containing a slight excess of water at ordinary temperatures or slightly above these.
For the manufacture of bleaching-powder, limestone of high degree of purity (especially free from magnesia and iron) is carefully burned so as to drive out nearly all the carbon dioxide without overheating the lime.
The bleaching-powder casks must be kept in a dry place, as cool as possible, and never exposed to the direct rays of the sun, in order to prevent a decomposition which now and then has even led to explosions.
About sixteen such chambers were combined in such manner that the fresh gas passed into that chamber which had been the longest time at work and in which the bleaching-powder was nearly finished, and so forth until the gas, now all but entirely exhausted, reached the last-filled chamber in which it met with fresh lime and there gave up the last of the chlorine.Advertisement
Bleaching-powder is manufactured to the extent of several hundred thousands of tons annually, almost entirely for the use of papermakers and cotton bleachers.
From 58.5 parts by weight of NaC1 we obtain theoretically 23Na = 40NaOH = 53Na2C03, together with 35.5 Cl, or zoo bleaching-powder.
As the weight of bleaching-powder consumed in the world is at most one-fifth of that of alkali, calculated as Na2C03, it follows that only about one-tenth of all the alkali required could be made by electrol y sis, even supposing the Leblanc process to be entirely abolished.
His services to industry included his improvements in the processes for the manufacture of sulphuric acid (1818) and oxalic acid (1829); methods of estimating the amount of real alkali in potash and soda by the volume of standard acid required for neutralization, and for estimating the available chlorine in bleaching powder by a solution of arsenious acid; directions for the use of the centesimal alcoholometer published in 1824 and specially commended by the Institute; and the elaboration of a method of assaying silver by a standard solution of common salt, a volume on which was published in 1833.
Chlorine may also be obtained by the action of dilute sulphuric acid on bleaching powder.Advertisement
For this purpose a filtered solution of bleaching-powder and a very dilute solution of nitric acid may be employed.
One of the most important derivatives of hypochlorous acid is bleaching powder.
By the action -of bleaching powder it is converted into chlorpicrin, CC1 3 NO 2.
In the process of bleaching by means of chlorine either bleaching powder or bichromates and hydrochloric acid are used.
Fleitmann, Ann., 1865, 134, p. 64); by the action of a ferrous or manganous salt with a salt of cobalt, nickel or copper on bleaching powder (G.
Antimony and its salts may be readily detected by the orange precipitate of antimony sulphide which is produced when sulphuretted hydrogen is passed through their acid solutions, and also by the Marsh test (see Arsenic); in this latter case the black stain produced is not soluble in bleaching powder solution.