Text-book of medical and pharmaceutical chemistry / by Elias H. Bartley.

  • Bartley, Elias Hudson, 1849-1937.
Date:
1898
Catalogue details

Licence: Public Domain Mark

Credit: Text-book of medical and pharmaceutical chemistry / by Elias H. Bartley. Source: Wellcome Collection.

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    Above this temperature it is a yellowish, pungent gas, resembling chlorine in many of its properties. It is a more powerful bleaching and disinfecting agent than chlorine, owing to the ease with which it decomposes. Water dissolves 200 times its volume of the gas, form- ing a colorless solution of hypochlorous acid. It sometimes decom- poses with a slight jar, or even spontaneously, separating into chlorine and oxygen. Hypochlorous acid is unimportant, but it forms a series of salts called hypochlorites. A solution of the sodium salt, liquor sodae chloratae (U. S. P.), (Labarraque's solution), potassium hypochlorite, liquor potassae chloratae, and calcium hypochlorite, occurring in chlorinated lime, are the most important compounds. Chlorous anhydride, C1203, has been shown to be a mixture of. C102 and free chlorine. Chlorine tetroxide, C1204, maybe obtained, as a yellow, explosive gas, by treating potassium chlorate with strong sulphuric acid. It is a powerful oxidizing agent. Below—200 C. (—40 F.) it is an orange-red liquid. It forms no corresponding acid. Chloric acid, HC103, and perchloric acid, HC104, are also known, but are very unstable, and, like those before mentioned, are powerful oxidizing agents. Potassium chlorate is the only salt of note, which will be described under potassium. Bromine and Oxygen.—No oxides of bromine are known. There are, however, three acids known, corresponding to those of chlorine. They are hypobromous acid, HBrO, bromic acid, HBr03, and perbromic acid, HBr04. They are of little impor- tance, and but one salt of the three acids is of interest to the physician, and that is sodium hypobromite, NaBrO, used as a reagent for the estimation of urea. It is prepared in solution by adding bromine to a solution of sodium hydroxide, taking care to keep the mixture cool by immersion in cold water. 2NaOH + Br2 = NaOBr + NaBr + H20. Iodine and Oxygen.—But one oxide of iodine is known with certainty—iodine pentoxide or iodic anhydride, I205. It is formed when iodic acid is heated to 1700 C. (3380 F.). Two oxygen acids are known—iodic, HI03, and periodic, HI04. The first is obtained by treating iodine with nitric acid, and the second by passing chlo- rine through a solution of iodine in water. 6H20 + I2 + 5C12 = 10HCI + 2HIO3. The first, when pure, appears as a white crystalline solid, and the second as colorless crystals. Both are very soluble in water, are easily decomposed, and form corresponding salts.