Saturated Bromine

Polythene wash bottles are sometimes charged with wash liquids other than water. Attention must be drawn to the fact that the components of some wash solutions may pass into the polythene and may be released into the space in the bottle when it is set aside repeated fillings and rinsings may be required to remove the chemicals from the bottle. It is safer to label the wash bottle and to reserve it for the special wash liquid. Such wash solutions include a weakly acid solution saturated with hydrogen sulphide, dilute aqueous ammonia, saturated bromine water, and dilute nitric acid. 

Finally, Eklund s group has described double-walled nanotubes (DWNT), with ca. 0.7 nm inner diameter and 1.4 nm outer diameter, that can form a three-layer cylindrical capacitor with a shell of bromine anions forming the outer electrode. Holes segregate on the outer nanotube, and saturation bromine doping creates 1 hole per 26 carbon atoms in the DWNT [135]. 

PH3 (g). The data of Ogier,1 who measured the heat of reaction between gaseous phosphine and saturated bromine water, yield, for PH3 (g), QJ— —3.6. Lemoult10 measured the heat of combustion of phosphine in oxygen to form H3P04, and his data yield, Q=309.8, whence, for PH3 (g), Qf= —6.3. The equilibrium data of Ipate v and Frost1 on the reaction, 4PH3 (g) =P4 (g) +6H2 (g), yield Q= —22.66, whence, for PH3 (g), Qf=2.34. We have been unable to interpret similar data obtained by Drummond.1... 

PbSe (c). Fabre1 found <2=40.1 for the reaction of aqueous lead acetate with gaseous hydrogen selenide whence, for PbSe (c), <2/=21.2, For the heat of solution of crystalline lead selenide in saturated bromine water to form lead selenate Fabre1 found 92.1 whence, for PbSe (c),... 

PbTe (c). Fabre3 found 104.5 for the heat of solution of solid lead telluride in saturated bromine water. These data yield, for PbTe (c), <2/= 19.1 or 6.0, depending upon whether tellurate or tellurite was formed. Fabre3 said that the product was tellurite, but in another experiment he found that tellurium dissolved under the same conditions to form tellurate. 

In the determination of sulfate, 2 to 5 g of the analysis sample is mixed with HC1 (2 volumes concentrated HC1 + 3 volumes of water), and the mixture is gently boiled for 30 minutes. After filtering and washing, the undissolved coal may be retained for the determination of pyrite sulfur, or it may be discarded and a fresh sample used for pyrite sulfur. Saturated bromine water is added to the filtrate to oxidize all sulfur forms to sulfate ions and ferrous ions to ferric ions. After boiling to remove excess bromine, the iron is precipitated with excess ammonia and filtered. This precipitate must be retained for the determination of nonpyrite iron if a fresh sample of coal was used for the determination of the pyrite iron. The sulfate is then precipitated with ISaCE, and the BaSC>4 is determined gravimetrically. 

While waiting for the paper to dry, you can perform the following short experiment. Weigh about 15 g of tomato paste in a beaker. Add about 30 mL of water and stir. Transfer the tomato juice into a 50-mL graduated cylinder and, with the aid of a pipet, add 5 mL of saturated bromine water (dropwise). With a glass rod, stir the solution very gently. Observe the colors and their positions in the cylinder. Record your observations on the Report Sheet. 

Saturated bromine water mix 5.5 g bromine with 150 mL water. Prepare in hood wear a face shield, rubber gloves, and a rubber apron. 

Place a drop of the test solution upon drop-reaction paper, and treat successively with 2 drops 3m sodium hydroxide and 1 drop saturated bromine water. Add 2 drops 1 1 ammonia solution remove the excess ammonia by waving the paper over a small flame. Add 2 drops reagent a blue colour develops. Sensitivity 1 pg Pb. Concentration limit 1 in 50,000. 

Place a drop of the test solution in mineral acid on a spot plate, introduce a drop of saturated bromine water followed by 2-3 drops 2m potassium hydroxide (the solution must be alkaline to litmus). Mix thoroughly, add a crystal of phenol, then a drop of the diphenylcarbazide reagent, and finally M sulphuric acid dropwise until the red colour (from the reaction between diphenylcarbazide and alkali) disappears. A blue-violet colouration is obtained. 

If iron was originally present in the tervalent state, it will be reduced to the iron(II) ions by H2S. It must be oxidized to iron(III) with concentrated nitric acid (or with a few drops of saturated bromine water) to ensure complete precipitation with NH4C1 and dilute NH3 solution. The original solution must be tested to determine whether the iron is present as Fe2+ or as Fe3 +. 

If magnesium is present, treat a drop of the solution on a spot plate with 2 drops of the reagent and 1 ml saturated bromine water. The original deep-blue colour becomes paler when the bromine is added, but remains more or less permanently blue. 

The bromination of purine nucleosides in aqueous solution has become a standard procedure. Thus, reaction of 2 -deoxyguanosine with saturated bromine water yields the 8-bromo derivative 8. °... 

Bromine water has been used as a reagent for the determination of sulfa drugs in bulk and in dosage forms by an indirect titrimetric method based on the reaction of sulfonamides with an excess of saturated bromine water to form the corresponding N- bromo derivatives. These derivatives on reaction with iodide release equivalent amounts of iodine which could be determined titrimetrically with thiosulfate by using starch as indicator. The recoveries range from 97.8 to 102.1% and the relative standard deviation is 0.1-2.2% (34). 

A saturated bromine aqueous solution can also be used to determine the type of amphoteric surfactant. Add 5 ml of 1 % sample solution to 1.5 ml saturated bromine aqueous solution. Observe the colour of the precipitate. Heat the mixture and observe the change in the precipitate. If the precipitate is a yellow to yellow-orange colour and is dissolved to form a yellow solution after heating, the sample is an imidazoline or alanine type of amphoteric surfactant. If the precipitate is a white to yellow colour and insoluble after heating, the sample is the other type of amphoteric surfactant. 

Bromine (Br, at. mass 79.91) is a dark red-brown liquid. Saturated bromine water contains 3.6% (w/v) of bromine (at 20°C). Bromine forms bromide (Br) and hypobromite (BrO ) in alkaline solution. The most stable forms of bromine are bromide and bromate (BrOa ). Bromide has reducing properties, whereas bromine (Br2), hypobromite, and bromate are oxidants. Many bromides are sparingly soluble compounds, and soluble bromide complexes are formed with the same metals as form soluble chloride complexes. 

Determination of 77. To the solution in 2 M HCl, add 1 ml of saturated bromine water and heat the solution (without boiling) until the yellow colour of the free bromine in the solution disappears. Cool the solution, transfer it to a separating funnel, add 2 ml of Rhodamine B solution, and shake the solution for 1 min with two portions of a mixture of CeHfe and CCI4 (2+1). Make up the combined extracts to the mark with the solvent in a 25-ml standard flask. Measure the absorbance of the solution at 560 nm, using the solvent or a reagent blank solution as reference. 

Extractive separation of 77. To the sample solution, containing not less than 50 pg of Tl, add 5 drops of saturated bromine water and cone. HCl until the HCl concentration is 6 M. Transfer the solution to a separating funnel and add 5 drops of the phenol solution. After 5 min, extract thallium by shaking for 1 min with two portions of DIPE. Wash the combined ethereal extracts by shaking with 3 ml of 6 M HCl. 

Organotin ccunpounds must first be decomposed before using the reagent [1 —3]. This can be done by first heating the chromatogram to 110°C for 30 min and then exposing it to saturated bromine vapors for 60 min (7—9 drops bromine in a... 

Reaction of Tryptophane. — Harlay also recommends the use of tryptophane to identify a tryptic digestion. Several drops of saturated bromine water, added to the liquids resulting from a pancreatic hydrolysis, cause the formation of a reddish yellow... 

Add 0.70 g of reagent-purity KBr and 0 ml of cone, sulphuric acid treated with 8 - 10 drops of saturated bromine water and distill the sample in a nitrogen flow (approx. 25 ml min.) until SO3 vapour appears. 

The bromine cyanide solution is prepared by adding 10% aqueous sodium cyanide solution to saturated bromine water, cooled in ice, imtil it is decolorised. 

In a small test tube, place 1-2 drops of the unknown (—20 mg if a solid) and add 1-2 mL of water. Check the pFl of the solution with pFl paper. In the HOOD hood, add saturated bromine water dropwise until the bromine color persists. A precipitate generally forms. 

Figure 3.33 Saturated bromine water and gaseous iodine... 

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