Ferric hydrate-How is it prepared? What is the advantage of keeping the ingredients on hand? Why is ammonia preferred to other alkalies as a precipitant? For what purposes is it used? When used as an antidote to poisoning by arsenic, how does it act? Does this preparation keep well? Ferric hydrate with magnesia-How is it made ? What is its use, and what are its advantages? Soluble ferric phosphate-How is it made? Is this a definite chemical compound? What other salt does it closely resemble? Describe odor, taste, chemical reaction, and solubility. Give tests for identity. What is the dose? Ferric pyrophosphate-How is this made? What is this salt chemically? In what respect does it differ from the salt which was formerly official? Describe odor, taste, chemical reaction, and solubility. Give tests for identity. What is the dose? -Ferric sulphate-Give Latin name, formula in symbols, and molecular weight. What is the British process for making this salt? Describe odor, taste, chemical reaction, and solubility. Give tests for identity. How may the following impurities be detected?-viz.: Ferric salt; copper. How much water of crystallization do the crystals contain? Dried ferrous sulphate-Give Latin name, formula in symbols, and molecular weight. How is it prepared? How many parts of the dried salt will one hundred parts of the crystallized salt make? Granulated ferrous sulphate-Give Latin name, formula in symbols, and molecular weight. Does this differ in composition from "ferri sulphas"? How is it prepared? What is the use of alcohol in this formula? What advantages does this powder possess over the ordinary form of crystals? Describe odor, taste, chemical reaction, and solubility. How may its quality be tested? Ferric valerianate Give Latin name, formula in symbols, and molecular weight. How may this salt be made? Describe odor, taste, chemical reaction, and solubility. Give tests for identity. What is the dose? Solution of ferric acetate-Give Latin name. How much anhydrous ferric acetate does it contain? Ferric acetate Give formula in symbols and molecular weight. How is the solution prepared? Describe odor, taste, chemical reaction, and solubility. Give tests for identity. How may the following impurities be detected ?—viz.: Zinc or copper; fixed alkalies; ferrous salt. What is the dose? Solution of iron and ammonium acetate-What is the Latin name? How is it made? What is its popular name? Is this preparation properly named? Why? What should it be called? What is the dose? Solution of ferric nitrate-Give Latin name. How much anhydrous ferric nitrate does it contain? Ferric nitrate-Give the formula in symbols and the molecular weight. Describe odor, taste, and chemical reaction. What is the dose? How may its quality be estimated? Solution of ferric subsulphate-Give Latin name. What synonymes has this solution? How much basic ferric sulphate does it contain? How is it prepared? Give description and specific gravity. Describe odor, taste, chemical reaction, and solubility. Give tests for identity. How may the following impurities be detected?-viz.: Nitric acid; ferrous salt. What is the dose? Solution of ferric tersulphate-What is the Latin name? What sulphate of iron does this solution contain, and how much? How is it made? Describe rationale of process. Wherein does this solution differ from the solution of ferric subsulphate? Describe odor, taste, chemical reaction, and solubility. Give tests for identity. How may the following impurities be detected?-viz.: Nitric acid; ferrous salt. For what is this solution used? Chromium-What is its formula in symbols? What is its molecular weight? How does it occur in nature, and whence is it obtained? What compounds does it form with oxygen? What are the tests for chromium salts? Chromic acid-What is the Latin name? What is its formula in symbols? What is its molecular weight? Describe odor, taste, chemical reaction, and solubility. Give tests for identity. What are its uses? Why should care be used in mixing it with deoxidizing bodies? CHAPTER XLV. NICKEL, COBALT, AND TIN. Ni; 58.6. Co; 58.6. Sn; 118.8. NEITHER of these metals nor any of their compounds are considered of sufficient medicinal importance to give them a place in the U. S. Pharmacopoeia. Their salts are sometimes used medicinally, and two of the metals are important in many respects, particularly in the arts. Nickel. Ni; 58.6. This metal is found in magnetic pyrites in Pennsylvania; also as arsenic or kupfernickel in Germany and Sweden, and as a silicate in New Caledonia. Its sp. gr. is 8.9. It is a white, malleable metal, and forms with copper a valuable alloy, known as German silver. This alloy is also used for making coins. Salts of nickel are very largely employed in electro-plating, and have come into use as medicines; the Latin name of the metal is Niccolum. Tests for Compounds of Nickel. 1. Ammonium sulphide produces with a solution of a nickel salt a black precipitate (sulphide), insoluble in diluted hydrochloric acid, but soluble in hot nitric acid. 2. Potassium or sodium hydrate produces with nickel salts pale green precipitates of hydroxide insoluble in an excess. 3. Potassium cyanide produces a green precipitate with a solution of a nickel salt, soluble in an excess, but reprecipitated by hydrochloric acid. Niccoli Bromidum, NiBr2. Nickel Bromide. Niccoli Cyanidum, NiCN2. Unofficial Salts of Nickel. By dissolving nickel carbonate in hydrobromic acid, concentrating, then crystallizing. By heating nickel chloride with an alkaline carbonate in sealed tubes and collecting the powder. By heating nickel filings to low redness in a stream of chlorine. By adding to a solution of potassium cyanide a solution of any nickel salt in slight excess and collecting the precipitate. Niccoli Sulphas, NiSO4.7H20. By dissolving pure nickel carbonate in diluted sulphuric acid, Nickel Sulphate. concentrating the solution, then crystallizing. Cobalt. Co; 58.6. This metal is usually found associated with arsenical ores. It is white, tough, and brittle, unalterable in the air, and strongly magnetic. Sp. gr. 8.5. It forms two classes of salts, cobaltous and cobaltic, in this respect resembling iron. The native ore skutterudite, CoAs,, and other cobalt minerals containing arsenic, are often sold in commerce under the name of flystone. It is used as a fly-poison by breaking it into small fragments and mixing them with sweetened water. The chloride and sulphocyanate have been used to make barometer paper, by dipping ordinary white paper into a solution and drying it when dry the color is blue, but an increase of moisture in the air changes the color to pink. Cobalt forms no official salts, and none of the unofficial salts are of pharmaceutical interest. Tests for Salts of Cobalt. 1. Ammonium sulphide produces in a solution of a cobaltous salt a black precipitate (sulphide), insoluble in diluted hydrochloric acid. 2. Solution of potassa produces with a solution of a cobaltous salt a blue precipitate, changing by heat first to a violet and subsequently to a red color. 3. Potassium cyanide produces a yellowish-brown precipitate, soluble in an excess; the clear solution after being boiled does not afford a precipitate with hydrochloric acid (difference from nickel salts). Tin. Sn; 118.8. The sulphide and oxide are the forms in which tin is usually found. Tin is a valuable white metal, of a silvery color, which, when bent, emits a peculiar crackling sound. Its sp. gr. is 7.3. It forms two classes of compounds, called stannous and stannic salts. These are not used to any extent in medicine or pharmacy, but are of great importance in the arts. Tests for Compounds of Tin. 1. Potassium or sodium hydrate produces in a solution of a salt of tin a white precipitate (hydroxide), soluble in an excess. 2. Ammonia water produces a white precipitate (hydroxide) with a solution of a stannous salt, nearly insoluble in an excess. The same reagent with a stannic salt produces a similar white precipitate (hydroxide), slightly soluble in an excess. 3. Ammonium sulphide produces in solutions of stannous salts a brownish-black precipitate, soluble in an excess (if an excess of sulphur be present in the reagent). The yellow sulphide is precipitated from this solution on the addition of an acid. Ammonium sulphide with stannic salts produces a yellow precipitate, soluble in an excess. 4. Mercuric chloride in contact with stannous salts is reduced to mercurous chloride or metallic mercury; no change occurs when it is added to stannic salts. Stanni Chloridum, SnCl2,2H2O. Sodii Stannas, Na2Sn03. Unofficial Salts of Tin. Acidum Metastannicum, 5SnO2,10H20. By dissolving tin in hot hydrochloric acid. By passing hydrogen sulphide gas into a solution of By boiling tin ore with solution of caustic soda. By acting on tin with nitric acid. CHAPTER XLVI. LEAD, COPPER, SILVER, AND MERCURY. Pb; 206.4. Cu; 63.18. Ag; 107.66. Hg; 199.8. THIS group embraces four well-known metals, which furnish compounds of great value as medicines. They are allied to one another chemically, although they differ greatly in their physical properties. Lead. Pb; 206.4. Lead is obtained from the native sulphide, galena, by roasting in a reverberatory furnace. It is often associated with silver. It is a heavy, soft, bluish metal, with a specific gravity of 11.45. Lead forms five compounds with oxygen: 1. Suboxide, Pb,O. 2. Monoxide, PbO. 3. Sesquioxide, Pb,O. 4. Dioxide, PbO. 5. Triplumbic tetroxide, Pb304 Tests for Compounds of Lead. 1. Hydrogen sulphide or ammonium sulphide precipitates the insoluble black sulphide from salts of lead. 2. Sulphuric acid or a sulphate causes the precipitation of the white sulphate, insoluble in nitric acid. 3. The alkaline carbonates (sodium, potassium, and ammonium) precipitate lead carbonate, insoluble in an excess. Poisonous Properties of Lead and its Compounds. Pure water dissolves appreciable quantities of lead through the formation of a slightly soluble hydroxide or carbonate. If traces of sulphates or chlorides be present in the water, an insoluble coating is formed on the surface of the metal, which protects it from further decomposition. Lead pipes and lead tanks for containing drinking-water should be used with care (see U. S. Dispensatory, 17th ed., page 1059). |