Inorganics, analysis

In similar circumstances, silver salts leave a residue of metallic silver lead and copper salts usually leave a residue of the corresponding oxide calcium and barium salts leave a resirlne of the carbonate or oxide. Identify the metal in all such cases by the usual tests of qualitative inorganic analysis. Metals other than the above are seldom encountered in elementan qualitative analysis. 

Absolute diethyl ether. The chief impurities in commercial ether (sp. gr. 0- 720) are water, ethyl alcohol, and, in samples which have been exposed to the air and light for some time, ethyl peroxide. The presence of peroxides may be detected either by the liberation of iodine (brown colouration or blue colouration with starch solution) when a small sample is shaken with an equal volume of 2 per cent, potassium iodide solution and a few drops of dilute hydrochloric acid, or by carrying out the perchromio acid test of inorganic analysis with potassium dichromate solution acidified with dilute sulphuric acid. The peroxides may be removed by shaking with a concentrated solution of a ferrous salt, say, 6-10 g. of ferrous salt (s 10-20 ml. of the prepared concentrated solution) to 1 litre of ether. The concentrated solution of ferrous salt is prepared either from 60 g. of crystallised ferrous sulphate, 6 ml. of concentrated sulphuric acid and 110 ml. of water or from 100 g. of crystallised ferrous chloride, 42 ml. of concentrated hydiochloric acid and 85 ml. of water. Peroxides may also be removed by shaking with an aqueous solution of sodium sulphite (for the removal with stannous chloride, see Section VI,12). 

A method for determining the SO, content of oleum is described in the author s Text Book 0/ Quantitative Inorganic Analysis Theory and Practice, Second Edition, 1951, p. 263 (Longmans, Green and Co. Ltd.). 

CAUTION. Ethers that have been stored for long periods, particularly in partly-filled bottles, frequently contain small quantities of highly explosive peroxides. The presence of peroxides may be detected either by the per-chromic acid test of qualitative inorganic analysis (addition of an acidified solution of potassium dichromate) or by the liberation of iodine from acidified potassium iodide solution (compare Section 11,47,7). The peroxides are nonvolatile and may accumulate in the flask during the distillation of the ether the residue is explosive and may detonate, when distilled, with sufficient violence to shatter the apparatus and cause serious personal injury. If peroxides are found, they must first be removed by treatment with acidified ferrous sulphate solution (Section 11,47,7) or with sodium sulphite solution or with stannous chloride solution (Section VI, 12). The common extraction solvents diethyl ether and di-tso-propyl ether are particularly prone to the formation of peroxides. 

If an appreciable amount of residue remains, note its colour. Add a few drops of water and test the solution (or suspension) with htmus or with Universal indicator paper. Then add a httle dilute hydrochloric acid and observe whether efiervesceiice occurs and the residue dissolves. Apply a flame test with a platinum wire on the hydrochloric acid solution to determine the metal present. (In rare cases, it may be necessary to subject a solution of the residue to the methods of qualitative inorganic analysis to identify the metal or metals present.) If the flame test indicates sodium, repeat the ignition of the substance on platinum foil. 

Hillebrand, W. F. Lundell, G. E. . Applied Inorganic Analysis, John Wiley and Sons New York, 1953. 

Basset, J. Denney, R. C. Jeffery, G. H. et al. VogeVs Textbook of Quantitative Inorganic Analysis, 4th ed. Longman London,... 

Sulcek, Z. Povondra, P. Methods of Decomposition in Inorganic Analysis. CRC Press Boca Raton, EL, 1989. 

Inorganic Analysis The most important precipitants for inorganic cations are chromate, the halides, hydroxide, oxalate, sulfate, sulfide, and phosphate. A summary of selected methods, grouped by precipitant, is shown in Table 8.1. Many inorganic anions can be determined using the same reactions by reversing the analyte... 

Inorganic Analysis Acid-base titrimetry is a standard method for the quantitative analysis of many inorganic acids and bases. Standard solutions of NaOH can be used in the analysis of inorganic acids such as H3PO4 or H3ASO4, whereas standard solutions of HCl can be used for the analysis of inorganic bases such as Na2C03. 

Inorganic Analysis Complexation titrimetry continues to be listed as a standard method for the determination of hardness, Ca +, CN , and Ch in water and waste-water analysis. The evaluation of hardness was described earlier in Method 9.2. The determination of Ca + is complicated by the presence of Mg +, which also reacts with EDTA. To prevent an interference from Mg +, the pH is adjusted to 12-13, precipitating any Mg + as Mg(OH)2. Titrating with EDTA using murexide or Eri-ochrome Blue Black R as a visual indicator gives the concentration of Ca +. 

Inorganic Analysis Redox titrimetry has been used for the analysis of a wide range of inorganic analytes. Although many of these methods have been replaced by newer methods, a few continue to be listed as standard methods of analysis. In this section we consider the application of redox titrimetry to several important environmental, public health, and industrial analyses. Other examples can be found in the suggested readings listed at the end of this chapter. 

Vogel s Textbook of Quantitative Inorganic Analysis, 4th ed. Longman London, 1981. 

E. Eeigl, Spot Tests in Inorganic Analysis, Elsevier Science Pubhshing Co., Inc., New York, 1958, pp. 372—375. 

I. M. Kolthoff and E. B. Sandell, Textbook of Quantitative Inorganic Analysis, MacMillan, New York, 1952, p. 534. 

The scientific interests of Anatoly K. Babko ranged widely, especially in regard to fundamental aspects of analytical chemistry, applications of organic reagents in inorganic analysis, chemistry of complex compounds (including heteropolyacids), analytical applications of complex compounds in photometry, luminescence and chemiluminescence, ion chromatography, and liquid-liquid extraction. 

This is primarily engaged in analysis of boiler water treatment matters and involves on-site studies of various problems and the chemical examination of corrosion products, boiler scales, etc. It can also carry out certain types of metallurgical, fuel and inorganic analysis. Normal wet methods of analysis coupled with a visible ultraviolet and atomic absorption spectrophotometer are used for a wide range of analytical applications. Equipment in use by the engineering insurers providing these services can include an ion chromatograph, spectrometer equipment, atomic... 

H Green, Recent uses of liquid ion exchanges in inorganic analysis Talanta, 1964,... 

In view of the selective character of many colorimetric reactions, it is important to control the operational procedure so that the colour is specific for the component being determined. This may be achieved by isolating the substance by the ordinary methods of inorganic analysis double precipitation is frequently necessary to avoid errors due to occlusion and co-precipitation. Such methods of chemical separation may be tedious and lengthy and if minute quantities are under consideration, appreciable loss may occur owing to solubility, supersaturation, and peptisation effects. Use may be made of any of the following processes in order to render colour reactions specific and/or to separate the individual substances. 

Fluorimetry is generally used if there is no colorimetric method sufficiently sensitive or selective for the substance to be determined. In inorganic analysis the most frequent applications are for the determination of metal ions as fluorescent organic complexes. Many of the complexes of oxine fluoresce strongly aluminium, zinc, magnesium, and gallium are sometimes determined at low concentrations by this method. Aluminium forms fluorescent complexes with the dyestuff eriochrome blue black RC (pontachrome blue black R), whilst beryllium forms a fluorescent complex with quinizarin. 

A, I, Vogel (1961), Text-Book of Quantitative Inorganic Analysis, 3rd edn, Longman,... 

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