When made from carbonate instead of potassium bicarbonate, what impurity is apt present? to be What are its physical properties and solubilities? How may it be identified? How may the following impurities be detected?—viz.: Carbonate; sulphate; chloride; tartrate. What are its medicinal uses? Give the dose. Into what official preparation does it enter? Give the Latin name, formula, and mode of preparation of efflorescent potassium citrate. Potassium cyanide-Give formula in symbols and molecular weight. What is the process for making this salt, which was formerly official? Explain the reaction which takes place between potassium ferrocyanide and potassium carbonate. In what form does it occur in commerce? Describe the physical properties of the official salt. What are its solubilities? How may it be identified? What per cent. of pure potassium cyanide should it contain, and how may this be tested? How may the impurity of carbonate be detected? What is the medicinal use of it, and what is the dose? What advantage has it over hydrocyanic acid? Rochelle salt-Give formula in symbols and molecular weight. How is this salt made? Explain the reaction which takes place. What is meant by saying that tartaric acid is a dibasic acid? Describe its physical properties and solubilities. How may its identity and purity be tested? What are the tests for the following impurities?-viz.: Calcium; sulphate; chloride; ammonium salts. What is its medicinal use, and what is the dose? Potassium ferrocyanide-Give formula in symbols and molecular weight. How is this salt made? What reaction takes place when potassium cyanide is mixed with ferrous carbonate in the presence of water? What renders this salt important? Describe its physical properties and solubilities. What are the tests for the following impurities ?—viz.: Carbonate; sulphate; chloride. Is this salt poisonous ? Of what importance is it chemically? Potassium hypophosphite - Give formula in symbols and molecular weight. How may this salt be prepared? Explain the reaction which takes place. Should the evaporation of the solution be conducted at a high heat or a low one? Why? How may the salt be rendered pure? Describe its physical properties and solubilities. How may it be identified? What are the tests for the following impurities?-viz.: Carbonate; calcium; sulphate; phosphate. Into what official preparation does it enter? What is the dose of it? Potassium iodide-Give formula in symbols and molecular weight. How is it prepared, and what reaction takes place? Should it be crystallized from an acid or an alkaline solution? Why? The presence of how much alkali is permitted by the official test? How may it be identified? What are the tests for the following impurities?—viz.: Iodate; more than about G.5 per cent. of chloride or bromide; sulphate. What are its uses, and what is the dose? Potassium nitrate-Give formula in symbols and molecular weight. Where does it come from? How is it made? Describe its physical properties and solubilities. How may it be identified? What are the tests for the following impurities?—viz.: Metals; alkaline earths; sulphate; chloride. What are its uses? What is the dose? Potassium permanganate-Give formula in symbols and molecular weight. What is the British process for making this salt? Explain the reactions which take place in its formation. Describe its physical properties and solubilities. How may its identity and purity be tested? How may the following impurities be detected?-viz.: Nitrate; chloride; sulphate. Why is the cautionary official note appended, as follows?-viz.: "It should not be brought in contact with organic or readily oxidizable substances." What renders it useful as a disinfectant, and what special care should be used in its application? How and why is it used chemically? Potassium sulphate-Give formula in symbols and molecular weight. How is this salt obtained? Describe its physical properties and solubilities. How may its identity and purity be tested? What are the tests for the following impurities?—viz.: Alkaline earths; metals; chloride. For what was it formerly used in pharmacy? What is now used as a substitute for it? Solution of potassium citrate-What is its official Latin name? How is it made? How much potassium citrate does it contain? What is the dose? CHAPTER XXXIX. THE SODIUM SALTS. THE sodium salts are generally more frequently used than those having potassium for their base, because they are relatively cheaper, and are often more soluble. The metal Sodium is a soft, malleable, ductile solid, which must be protected from the oxygen of the air by being constantly immersed in petroleum or naphtha. Tests for Sodium Salts. Sodium may be recognized in its salts by the following reactions: 1. The intensely yellow color produced when even a trace of a sodium compound is introduced into a colorless flame. 2. A reliable and practical precipitant is yet to be discovered for the sodium salts, because the compounds are generally very soluble. Neutral solutions may be precipitated by potassium metantimoniate: this reaction, however, has but a limited application. 3. Sodium salts are generally colorless, and not volatile below a red heat. Sodii Carbolas, NaCeН50. Sodium Carbolate. . Preparation. By treating acid calcium phosphate with sodium car bonate. By heating sodium phosphate to redness, dissolving and crystallizing. By treating common salt with sulphuric acid. By decomposing sodium carbonate with sulphurous acid. By dissolving sodium hydrate in water. Double decomposition between chlorinated lime and sodium carbonate. 1 per cent. solution of exsiccated sodium arsenate. Solution of sodium silicate. Each contains three grains of sodium bicarbonate. By decomposing sodium carbonate with acetic acid. Unofficial Sodii Citras, 2C6H5Nа307.11H20. Sodii-Citro-Tartras Effervescens. Effervescent Sodium Citro-tartrate. Preparations of Sodium. Sodii et Ammonii Phosphas, NH4NaHPO4.4H20. Sodium and Ammonium Phosphate. Sodii et Argenti Hyposulphis, 2Na2S¿03 + Sodium and Silver Hyposulphite. Sodium Ethylate. Sodii Nitro-Prussidum, Na2Fe(CN),NO.2H20. Sodium Nitro-Prusside. Add metallic sodium to carbolic acid, and allow it to crystallize. Saturate a solution of citric acid with sodium bi carbonate, evaporate, and allow it to crystallize. 17 p. sodium bicarbonate; 8 p. tartaric acid; 6 p. citric acid. Mix, and place in a dish heated to about 200° F. Stir constantly until a granular salt is obtained. Lastly, sift it. Dissolve 5 p. crystallized sodium phosphate and 2 p. ammonium phosphate in 20 p. hot water; then add ammonia water until the liquid is alkaline, and crystallize. Dissolve freshly precipitated silver oxide in a solution of sodium hyposulphite, and evaporate to crystallize. Caustic. Used in alcoholic solution; also applied externally mixed with olive oil. Digest 1 p. potassium ferrocyanide with 2 p. nitric acid and 2 p. water until it ceases to produce a blue precipitate with iron salts. When cool, neutralize the mother-liquid with sodium carbonate, then collect the red crystals. Sodii et Platini Chloridum, 2NaCl.PtCl4. Dissolve 3 p. platinic chloride and 5 p. sodium 6H20. Sodium and Platinum Chloride. Sodii Silicas, Na2SiO3. Sodium Silicate. Sodium Silico-Fluoride, Na2SiF6. Sodii Stannas, Na2SnOз. Sodium Stannate. Sodii Sulphobenzoas, CH1(NaSO3)COONa. Sodii Ethylsulphas, C2H5NaSO4.H20. Sodii Tartras, Na2C4H4O6.2H2O. Sodium Tartrate. Sodii Valerianas, NaC¿H902. Sodium Valerianate. chloride in water, and evaporate to dryness, stirring continually. Mix 1 p. silica and 2 p. dried sodium carbonate; fuse in an earthen-ware crucible, and pour the mass on a slab. Dissolve in water, filter, and concentrate to crystallize. Antiseptic. A mild caustic. Fuse tin-ore with soda and sodium nitrate. Non-poisonous antiseptic. Cathartic. The dose for children is from 2 to 3 drachms. Dissolve 6 p. tartaric acid and 74 p. sodium bicarbonate, each separately, in water. Mix the solutions, filter, and concentrate to crystallize. Saturate valerianic acid with sodium carbonate. SODA. U. S. Soda. NaOH; 39.96. [SODIUM HYDRATE. SODIUM HYDROXIDE. CAUSTIC SODA.] Preparation.-Owing to the improvements in the manufacture of metallic sodium and the cheapening of the product, soda can be found in commerce which has been made by oxidizing the metal by bringing it in contact with water and evaporating the pure solution of soda. When the pure hydrate is not needed, the white caustic soda, in sticks, made by evaporating a solution of soda (see Liquor Soda) and casting the fused residue into moulds, is used. (See Potassa, page 524.) SOLUBILITY. Soda. U.S. Dry, white, translucent pencils, or fused masses, showing a crystalline fracture. Great caution is necessary in tasting and handling it, as it rapidly destroys organic tissues. Exposed to the air, it rapidly deliquesces, absorbs carbon dioxide, and becomes covered with a dry coating of carbonate. TESTS FOR IDENTITY AND QUANTITA- IMPURITIES. TESTS FOR IMPURITIES. The aqueous solution of Soda should be colorless. Nor by the subsequent addition of ammonia water in The remainder of the acidulated solution should not be rendered turbid by ammonium oxalate T.S. If a solution of 1.2 Gm. of Soda in 10 C.c. of water be slightly supersaturated with nitric acid, then 0.5 C.c. of decinormal silver nitrate V.S. added, and the precipitate, if any, removed by filtration, the clear filtrate should remain unaffected by the further addition of silver nitrate V.S. If to a solution of 2.5 Gm. of Soda in 10 C.c. of water, strongly supersaturated with hydrochloric acid, 0.1 C.c. of barium chloride T.S. be added, and the precipitate, if any, removed by filtration, the clear filtrate should remain unaffected by the further addition of barium chloride T.S. If 0.7 Gm. of Soda be dissolved in 1.5 C.c. of water, and After boiling this alcoholic solution with 5 C.c. of cal- |