Bromate and bromide

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). 

Determination of carbonate by the evolution of carbon dioxide Discussion. The 

The decomposition of the carbonate may be effected with dilute hydrochloric acid, dilute perchloric acid, or phosphoric(V) acid. The last-named acid is perhaps the most convenient because of its comparative non-volatility and the fact that the reaction can be more easily controlled than with the other acids. If dilute hydrochloric acid is employed, a short, water-cooled condenser should be inserted between the decomposition flask and the absorption train (see below). 

Two absorbents are required, one for water vapour, the other for carbon dioxide. The absorbents for water vapour which are generally employed are (a) anhydrous calcium chloride (14-20 mesh), (b) anhydrous calcium sulphate ( Drierite or Anhydrocel ), and (c) anhydrous magnesium perchlorate ( Anhydrone ). Both (b) and (c) are preferable to (a) (c) absorbs about 50 per cent of its weight of water, but is expensive. Anhydrous calcium chloride usually contains a little free lime, which will absorb carbon dioxide also it is essential to saturate the U-tube containing calcium chloride with dry carbon dioxide for several hours and then to displace the carbon dioxide by a current of pure dry air before use. 

The absorbent for carbon dioxide in general use is (d) soda-lime (this is 

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It is necessary to maintain this reaction below 0°C to minimize the disproportionation of hypobromite to bromate and bromide. 

Action of bromine or iodine on a warm concentrated solution of KOH forms bromate and bromide or iodate and iodide, respectively ... 

Fig. 5. Strategies for isotope dilution analysis utilizing on-line coupling IC-ICP-MS. Shown is the separation of bromate and bromide by anion IC.The sample was 585 )Lll of a bottled water, spiked with bromate and a bromate isotope standard. The column, eluent and detection device are as described in Fig. 4. Shown are the mass traces form/z79 and 81 (dotted line) and the total time slice isotope ratio for m/z 79/81.

So far, only the bromites of barium, lithium, and strontium have been prepared,2 by heating the corresponding bromate and bromide together. The method should be applicable to other bromites as well. So far, very little is known of these salts, except that heating produces the bromide... 

Hydrobromic acid Mix together solutions of potassium bromate and bromide, and acidify with dilute sulphuric acid bromine is liberated as a result of interaction between the bromic and hydrobromic acids set free. The bromine may be extracted by adding a little chloroform or carbon tetrachloride. 

Measurements have also been made with molten alkali nitrate systems by Duke et . In sodium nitrate at 350 °C, the reaction is first-order in both bromate and bromide, with k equal to 2x 10" l.mole" .sec" and substantial variation on adding other cations. When zinc bromide is present, the results are consistent with the mechanism... 

The bromine is blown out with air and absorbed in Na2C03 solution to give bromate and bromide. On acidification the element can be distilled off ... 

For the estimation of diph4nytamim the powder may be saponified as above, and then distilled until all the diphen amtne has passed over. The distillate is extracted with ether, which is separated, dried with calcium chloride and evaporated. The diphenylamine may also be estimated by conversion to tetrabromo diphcnylamine. For this purpose the ethereal solution is evaporated with atcohalcoholic solution with stirring. The tetrabromo-diphenylamine separates out, and the supernatant liquor should be dear and should smell distinctly of bromine. Water is added and the whole is boiled to remove alcohol and bromine. The bromine compound is filtered oiF, washed with warm water and dried in a steam oven. The bromination may also be ejected by potassium bromate and bromide in acid solution. 

A 3.650-g sample containing bromate and bromide was dissolved in sufficient water to give 250.0 mL. After acidification, silver nitrate was introduced to a 25.00-mL aliquot to precipitate AgBr, which was filtered, washed, and then redissolved in an ammoniacal solution of potassium tetracyanonickelate(II) ... 

Unsaturated Products. The irradiated sample was condensed at 77 °K. An excess of a standard acid solution of bromate and bromide was added, and the temperature was raised. When the reaction was complete, the mixture was treated with excess iodide. Free iodine was titrated with thiosulfate. A blank analysis was substracted from the measured volume. 

HypoRBoMou.s Acid—HBrO—97—is obtainecl, in aqueous solution, by the action of Br upon mercuric oxide, silver oxide, or silver nitrate. When Br is ailded to concentrated solution of potassium hydrate, uo Uypobro-mite is formed, but a mixture of bromate and bromide, having no decol-orixiug action. With sodium hydrate, however, sodium bypobromite is formed in solution and such n solution, freshly prepared, is used in Knop s... 

Procedures based on the reaction of phenelzine sulfate with iodine in bicarbonate solution (2) and in sodium hydroxide (16) and with bromate and bromide in acid solution (16) with subsequent titration of excess reagent (iodine or bromide converted to iodine) in acid solution with thiosulfate have been reported. 

At equilibrium, molecular bromine is in great abundance over the ionic species, bromate and bromide, in acidic solution. In neutral or basic solution, this distribution is reversed. 

Another pathway to explain the oxidization is possible. In a first reaction, a disproportionation of hypobromite ions into bromate and bromide ions would occur according to... 

Preparation by reaction of potassium bromate and bromide on 2,4-diethyl-6-hydroxyacetophenone in solution of acetic acid-carbon tetrachloride mixture (quantitative yield) [2965],... 

Bromine disproportionates to bromate and bromide whether the alkali is hot or cold. The reaction is analogous to the chlorine reaction in hot alkali (Equation 6.36). The bromate ion will be pyramidal like chlorate (Structure 6.5). 

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