Lead acetate reagent

A. Sulfur Test.—To 1 cc. of the filtrate made slightly acid with acetic acid, add a few drops of lead acetate reagent. A black precipitate of PbS show s the presence of sulfur. 

Dilead hexacyanokisferrate [14402-61 -0] Pb2[Fe(CN)g], is a white precipitate that forms when lead acetate is added to Ca2[Fe(CN)g]. It is insoluble in water or dilute acids but is soluble in hot ammonium chloride or ammonium succinate solutions. It has been used as a quaUtative analytical reagent in tests for cadmium and chromate. 

Basic Lead Acetate. Basic lead acetate [1335-32-6] (lead subacetate), 2Pb(0H)2-Pb(C2H3 02 )2, is a heavy white powder which is used for sugar analyses. Some physical properties are given in Table 4. Reagent grade is available in 11.3-kg cartons and in 45- and 147-kg fiber dmms. 

Fig. 2 The influence of the reagent concentration on the sensitivity of detection detection of equal amounts of luteolin with basic lead acetate solution that was (A) undiluted, (B) diluted 1 + 4 and (C) diluted 1 + 50.

Sodium hydroxide, 10% in water. Dissolve 10 g of NaOH in 100 mL of distilled water Lead acetate, 30% in water. Dissolve 30 g of acetate in 100 mL of distilled water Stannous chloride solution. Dissolve 40 g of reagent in 100 mL of concentrated hydrochloric acid... 

Sunshine (10) and Clarke (6) give two microcrystal tests, both from aqueous solution (a) lead iodide-potassium acetate reagent forms dense rosettes ... 

Mercury nitrate, corrosive sublimate, white arsenic, and lead acetate are occasionally used as reagents, and soap is described as an indication of hard waters, as when added to them a decomposition takes place, the acid unites with alkali, and the oil is disengaged such waters as these are generally called hard waters, and are unfit for washing cloaths, as also for boiling pulse and the harder kinds of flesh. 18 The list of qualitative reagents for the many constituents of natural waters comprises the principal reagents in use at present. 

ANALYZER (Reagent-Tape). The key to chemical analysis by this method is a tape (paper or fabric) that has been impregnated with a chemical substance that reacts with the unknown to form a reaction product on the tape which lias some special characteristic, e.g., color, increased or decreased opacity, change in electrical conductance, or increased or lessened fluorescence. Small pieces of paper treated with lead acetate, for example, have, been used manually by chemists for many years to determine the presence of hydrogen sulfide in a solution or in the atmosphere. This basic concept forms the foundation for a number of sophisticated instruments that may pietreat a sample gas, pass it over a cyclically advanced tape, and, for example, photo-metrically sense the color of the exposed tape, to establish a relationship between color and gas concentration. Depending upon tile type uf reactiun involved, the tape may he wet or dry and it may be advanced continuously or periodically. Obviously, there are many possible variations within the framework of this general concept. 

Aqueous solutions of calcium chloride, ferric chloride or silver nitrate give precipitates or colorations with certain organic acids which are valuable for the detection of these acids. It is important to use neutral solutions of the acids which at the same time do not contain metallic radicles likely to react with the reagents added. Thus the addition of calcium chloride to a solution of lead acetate may produce a precipitate of lead chloride. A neutral solution, which should be of about 10% concentration, prepared as follows, usually avoids such complications —... 

All metal salts were reagent grade. Doubly deionized water was used to prepare the solutions of 0.1N metal ion. The lead acetate solutions were filtered through a Millipore filter in order to remove a slight turbidity. 

Ruthenium red (ammoniated ruthenium oxychloride) is a strong indicator of the polycarboxylic acid groups in pectin. This reagent is made by adding enough ruthenium red powder to 10% lead acetate to produce a wine-red color. 

Lead acetate or lead nitrate solution first no change, but on further addition of the reagent a white precipitate of lead thiosulphate is formed ... 

The test is usually carried out by adding the reagent to the solution acidified with dilute hydrochloric acid carbonates, sulphites, and phosphates are not precipitated under these conditions. Concentrated hydrochloric acid or concentrated nitric acid should not be used, as a precipitate of barium chloride or of barium nitrate may form these dissolve, however, upon dilution with water. The barium sulphate precipitate may be filtered from the hot solution and fused on charcoal with sodium carbonate, when sodium sulphide will be formed. The latter may be extracted with water, and the extract filtered into a freshly prepared solution of sodium nitroprusside, when a transient, purple colouration is obtained (see under Sulphides, Section IV.6, reaction 5). An alternative method is to add a few drops of very dilute hydrochloric acid to the fused mass, and to cover the latter with lead acetate paper a black stain of lead sulphide is produced on the paper. The so-called Hepar reaction, which is less sensitive than the above two tests, consists of placing the fusion product on a silver coin and moistening with a little water a brownish-black stain of silver sulphide results. 

Heat with sodium carbonate and potassium nitrate This test may be carried out in a loop of platinum wire or upon platinum foil or upon a piece of broken porcelain. If chromium is present, a yellow melt is produced. This should be dissolved in water, acidified with dilute acetic acid, and (a) silver nitrate solution added, when brownish-red silver chromate is precipitated, (6) lead acetate solution added, when yellow lead chromate is precipitated, or (c) 1-2 ml diphenylcarbazide reagent added, when a deep-red colouration is produced. 

Lead Paper. This reagent for hydrogen sulfide, is prepared by soaking filter paper in a solution containing 5 grams of lead nitrate per liter, and drying in air free from H2S. Instead of this paper, one can use paper moistened widi ferrous sulfate or lead acetate solution. 

Lead tetraacetate reacts poorly with acyclic alkanes, even 3-methylpentane, although cyclohexane is readily converted to the corresponding acetate at 80 C or with irradiation at room temperature.The yield of acetate is increased 10-fold by the addition of Bu OH, under which conditions BuKD- is thought to act as H-atom abstractor. " The more reactive lead(IV) reagent Pb(OCOCF3)4 has been used to introduce the trifluoroacetate group. Hexafluorobenzene or CF3CO2H are satisfactory solvents and hydrolysis to the alcohol is easily accomplished with NaOH, with an overall yield of ca. 4S%. The secondary C—H bonds are attacked in n-alkanes and arenes also react under these conditions." ... 

Transfer 3 ml of the digested SMnple to tiie arsine generating vessel, add sufficient water to produce 35 ml, and then add 5 ml of hydrochloric acid, 2 ml of a 15% solution of potassiiun iodide, and 0.5 ml of Staimous Chloride Reagent (40%) swirl the solution, and allow to stand for 15 minutes. Insert a pad of glass wool moistened witii lead acetate solution into the lower tube of tiie generating vessel. Introduce 3 ml of the Silver DDC Solution into the absorber tube, and 3 g of grMiulated zinc into the flask. Mid immediately assemble the two parts of tiie apparatus. Allow tiie evolution of arsine to continue for 1 hour. Transfer the Silver DDC... 

For purification, the crystalline hexaatomic sulfur is dissolved in benzene (approx. 100 mg./l.) toluene is not suitable (see Properties). The benzene solution is extracted with a series of reagents, three or four extractions being made with each reagent except where otherwise indicated. (For 200 ml. of benzene solution, 50-ml. portions of reagent are used). The reagents are employed in the following order (1) water, (2) 10% aqueous potassium triiodide, until the benzene phase remains colored from iodine, (3) 10% aqueous potassium iodide, (4) water, (5) 5% aqueous lead acetate, twice, (6) water, (7) 5 % aqueous potassium hydroxide, once, (8) water. The purified solution is dried over magnesium sulfate and should be used immediately. The approximate concentration of Sg can be determined spectro-photometrically at 300 mju (e = 181 l./g.-atom) after suit-... 

Amphetamines have also been associated with a syndrome of acute kidney injury and rhabdomyolysis. Several series have described patients following intravenous injection of methamphetamine or phenmetrazine who presented with hyperactivity, fever, chills, sweats, abdominal cramps, diarrhea, and hypotension [177,178]. The patients have developed acute kidney injury which is usually oliguric and associated with classic rhabdomyolysis, similar to cases of cocaine-induced rhabdomyolysis. Several patients have had disseminated intravascular coagulation and liver function abnormalities as well. Methamphetamine abuse has also been associated with accelerated hypertension, unexplained chronic renal failure, acute lead poisoning (a common reagent used in its production utilizes lead acetate) and at least one case of biopsy proven interstitial nephritis the latter patient responded to intravenous corticosteroids but whether the nephritis was truly due to amphetamines remains unproven [179]. 

Oxidation reactions also include those reactions that involve the formation of new carbon/oxygen bonds. We have already seen an example the addition of hydrogen peroxide to a carbon/carbon double bond to give the 1,2-diol. Such compounds may undergo further oxidation by treatment with periodic acid, HI04, or lead acetate, Pb(OAc)4. These two reagents are complementary, as the... 

The functions of the reagents used in the reduction of arsenic compounds, such as Zn, HCl, NiCla, SnCh, and KI are discussed below in connection with the Gutzeit method. Sodium borohydride also has been proposed as the reducing agent [39-42]. Sequential spectrophotometric determination of As(III) and As(V) is possible by using borohydride [40]. Hydrogen sulphide, which interferes in the reaction, is separated from arsine on cotton wool impregnated with lead acetate. 

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