Silver bromide, determination

Similar remarks apply to the determination of bromides the Mohr titration can be used, and the most suitable adsorption indicator is eosin which can be used in dilute solutions and even in the presence of 0.1 M nitric acid, but in general, acetic (ethanoic) acid solutions are preferred. Fluorescein may be used but is subject to the same limitations as experienced with chlorides [Section 10.77(b)], With eosin indicator, the silver bromide flocculates approximately 1 per cent before the equivalence point and the local development of a red colour becomes more and more pronounced with the addition of silver nitrate solution at the end point the precipitate assumes a magenta colour. 

Bromides can also be determined by the Volhard method, but as silver bromide is less soluble than silver thiocyanate it is not necessary to filter off the silver bromide (compare chloride). The bromide solution is acidified with dilute nitric acid, an excess of standard 0.1M silver nitrate added, the mixture thoroughly shaken, and the residual silver nitrate determined with standard 0.1 M ammonium or potassium thiocyanate, using ammonium iron(III) sulphate as indicator. 

Discussion. These anions are both determined as silver bromide, AgBr, by precipitation with silver nitrate solution in the presence of dilute nitric acid. With the bromate, initial reduction to the bromide is achieved by the procedures described for the chlorate (Section 11.56) and the iodate (Section 11.63). Silver bromide is less soluble in water than is the chloride. The solubility of the former is 0.11 mg L 1 at 21 °C as compared with 1.54 mg L 1 for the latter hence the procedure for the determination of bromide is practically the same as that for chloride. Protection from light is even more essential with the bromide than with the chloride because of its greater sensitivity (see Section 11.57). 

Periodates are also reduced by sulphurous acid, and may therefore be similarly determined. Similar remarks apply to bromates these are ultimately weighed as silver bromide, AgBr. 

AgBr, light sensitivity of, 19 360. see also silver bromide AGDOC service, 18 244 Age. See also Aging Dating influence on toxicity, 25 212 using radioactive decays to determine, 21 316... 

The atomic weight of bromine.—The at wt. of bromine has been determined by methods which follow in principle those employed for chlorine. A. J. Balard (1826),14 the discoverer of bromine, transformed a known weight of potassium bromide into the sulphate, and also reduced silver bromide to metallic silver by means of zinc the numbers 74 7 and 75 3 were respectively obtained. J. von Liebig (1826)... 

The stock solution, ca. 0.3 mol dm-3, of hydrobromic acid was prepared from a twice-distilled sample of the hydrobromic acid. Its bromide content was determined gravimetrically as silver bromide. Triplicate runs agreed to within 0.02%. The silver + silver bromide electrode was of the thermal type, prepared by heating twice recrystallized silver bromate (10 mass percent) and silver oxide (90 mass percent) at a temperature of 820° K. The preparation of the silver oxide, the preparation of the hydrogen electrodes, the design of the cell, the purification of the hydrogen gas, and other experimental techniques, have been described earlier (13,14,15). The water bath in which the cells were immersed was controlled to within 0.02°K. 

Samples were analyzed for cobalt, bromine, and ammonia. The cobalt was weighed as cobalt sulfate, and the bromine as silver bromide. Ammonia was determined by the Kjeldahl method. 

A Study Requiring High Precision Determination of the Thickness of a Gelatin Layer Adsorbed on Silver Bromide... 

The ability to make very precise measurements has allowed us to use the disk centrifuge to determine the thickness of adsorbed gelatin layers on silver bromide particles (4). When particles are coated with an adsorbed polymer layer, the sedimentation time reflects the size and density of the particle core as well as the thickness and density of the adsorbed layer. An apparent (incor-... 

The MO calculations explain a possible route for silver cluster formation and catalysis in silver bromide. The electron affinity of the silver center determines... 

Tubandt was a pioneer of - solid state electrochemistry. He introduced a methodology to determine the - transport numbers of ions in -> solid electrolytes [i], which is now referred to as -> Tubandt method. Together with his co-workers he performed seminal studies of conductivities and transport numbers of solid electrolytes, e.g., of silver, lead, and copper halides, and silver sulfide. He showed for the first time that the entire dark current of silver bromide is transported by silver ions, and also that slightly below the melting point silver iodide has a higher conductivity than the melt. 

In 1897-1899, the work of Richards and Baxter4 on the atomic weight of cobalt was published. Anhydrous cobaltous bromide was prepared by direct union of the pure elements and the product sublimed in a stream of hydrogen bromide and nitrogen. The bromine in the salt was determined by the two usual methods, the amount of silver required to precipitate it being first measured and then the precipitated silver bromide being collected and weighed. The final results were as follow ... 

Neither silver bromide nor iodide react thus, and it is possible to estimate silver chloride in presence of iodides by means of this reaction, the excess of potassium ferroeyanide remaining after filtration being determined by titration with standard permanganate.3... 

The standard potential of the silver-silver bromide electrode has been determined from emf measurements of cells with hydrogen electrodes and silver-silver bromide electrodes in solutions of hydrogen bromide in mixtures of water and N-methylacetamide (NMA). The mole fractions of NMA in the mixed solvents were 0.06, 0.15, 0.25, and 0.50, and the dielectric constants varied from 87 to 110 at 25°C. The molality of HBr covered the range 0.01-0.1 mol kg 1. Data for the mixed solvents were obtained at nine temperatures from 5° to 45°C. The results were used to derive the standard emf of the cell as well as the mean ionic activity coefficients and standard thermodynamic constants for HBr. The information obtained sheds some light on the nature of ion-ion and ion-solvent interactions in this system of high dielectric constant. 

The stock solution of HBr was prepared from HBr obtained by double distillation of commercial 48% HBr solution. In each distillation the first and third fractions were discarded. The product was diluted to a molality (m) of 1.0 mol kg 1 and the concentration determined to within 0.01% by weighing silver bromide. 

In this respect adsorption of dyes has been popular, especially because their colour allows rapid and accurate spectroscopic detection in the supernatant. However, caveats (i) and (il) above also apply to these adsorbates. For a discussion the reader may consult the proceedings of a symposium devoted to surface area determination in general containing a contribution by Padday in which the outcome of a comparative survey over 19 different laboratories was reported, dealing with the adsorption of the dye 1,1 - diethyl-2,2 cyanine on silver bromide and a few other adsorbents. Giles et al. have given a list of recommended a -values ... 

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