Ceric Sulfate Solution Research Articles

Titrimetric determination of molybdenum (V) and uranium(IV) with ceric sulphate using rhodamine 6G as a fluorescent indicator

1. Conditions have been developed for the titrimetric determination of molybdenum(V) and uranium(IV) with ceric sulphate at the room temperature using rhodamine 6 G as an internal fluorescent indicator. This indicator functions very satisfactorily even in the diffuse light of the laboratory, the fluorescence being quenched suddenly at the equivalence point on the addition of a very slight excess of cerium(IV) sulphate solution. The indicator correction is negligible in titrations with 0.05 N ceric sulphate solution. 2. Titrations of molybdenum(V) can be done in media containing hydrochloric acid in the concentration limits 2.0–4.0 N. When the acid concentration is 1.0 N and below, the titration is complicated by the formation of molybdenum blue. The rhodamine 6 G indicator appears to function more satisfactorily than the ferroin indicator. 3. Titrations of uranium(IV) with ceric sulphate, using the rhodamine 6 G as internal indicator, can be satisfactorily carried out in media containing sulphuric acid in the concentration limits 1–5.0 N. The Rhodamine 6 G indicator is not subject to the limitations of the ferroin indicator. 4. A detailed investigation has been made to elucidate the mechanism of the functioning of rhodamine 6 G as a fluorescent indicator in the titration of molybdenum(V) and uranium(IV) with ceric sulphate. Evidence is presented to show that rhodamine 6 G works very likely as a true redox indicator.

The rapid determination of tungsten after reduction with bismuth amalgam

A titrimetric determination of tungsten is described; it is based on reduction of tungsten to tungsten (V) by bismuth amalgam in concentrated hydrochloric acid solution and titration with ceric sulphate solution. The end-point can be detected potentiometrically or visually. The method may be extended to the determination of tungsten in a steel.

Suggested Method for Iodide Determination

This article presents a modification of the method of iodide determination by Lein and Schwartz that takes less than an hour. The general principle is discussed, along with the following topics: interferences; apparatus including colorimetric equipment, spectrophotometer, filter photometer, and timer; reagents including acid‐permanganate solution, salt‐arsenite solution, ceric sulfate solution, stock iodide solution, working iodide solution, and hypochlorite solution; procedure; calculations; and precision and accuracy.

Cerimetric Determination of Molybdenum in High Chloride Media Using Molybdenum Blue Reaction

A new volumetric method of determining molybdenum in a high chloride media is described. After passage through a Jones reductor the reduced molybdenum is caught under a receiver solution of sodium molybdate whose pH is so adjusted that an equivalent amount of molybdenum blue is formed. The molybdenum blue is then titrated to a colorless equivalence point with standard ceric sulfate solution. The formation of molybdenum blue serves two purposes: the oxidationreduction reaction between Mo(III) and Mo(VI) forms an intermediate oxidation state that is stable against air oxidation and the intermediate oxidation state, molybdenum blue, serves as its own indicator in the titration. The results obtainable by this method are comparable to those obtained by the use of the permanganate method in sulfuric acid. (auth) The fluorescent x-ray determination of tantalum in riobium is described A concentration range of 0.05 to 0.70% is covered The oxide-cellulose pellet is placed in the sample holder and the surface irradiated. The fluorescent x radiation from the pellet is dispersed and the integrated intensity of the analytical line is compared to that of a non- dispersed beam from an external standard. The recorded intensity ratios are referred to an appropriate analytical curve to obtainmore » the tantalum concertration (auth)« less

各種水溶液試料中のネプツニウム-239の定量法

>All neptunium of (IV), (V), and (VI) states in urine is quantitatively coprecipitated onto basic phosphates of calcium and magnesium which are formed when the sample is treated with sodium hydroxide. The determination of neptunium is studied using this coprecipitation procedure. Neptunium can be concentrated by the coprecipitation from large volumes of aqueous samples such as urine, tap water, and sea water. Separation from other radioactive nuclides which are simultaneously coprecipitated onto the precipitate can be attained by the anion exchange. For urine samples basic phosphates of calcium and magnesium were directly precipitated by adding sodium hydroxide solution. For tap water, phosphoric acid and a small amount of the calcium carrier were added in order to carry down neptunium. In the case of sea water, phosphoric acid was added and a small portion of calcium and magnesium phosphates were precipitated by adding a small amount of sodium hydroxide. The precipitate was dissolved with nitric acid. The resultant solution contained 7.5N nitric acid, 0.1M semi-carbazide, and 0.01M ferrous sulfamate. The solution was passed through 1.00 g of Dowex 1 x 8 resin column and washed with the nitric acid-reductant solution, then eluted the adsorbed neptunium with a small amount of 0.2Nmore » nitric acid 0.005M ceric sulfate solution. The recoveries of Np/sup 239/ were 97.0 2.6% for 300 ml of human urine, 97.9 3.1% for 1000 ml of tap water, and 96.4 2.2% for 1000 ml of sea water, respectively. (auth)« less

Volumetric estimation of thorium by ferrocyanide

Precipitation of ThFe(CN)6 from a solution of thorium nitrate with potassium ferrocyanide at varius concentrations has been carried out for the estimation of thorium. The precipitate was filtered and the excess of ferrocyanide was titrated with standard ceric sulphate solution. The amount of potassium ferrocyanide thus used was obtained and the amount of thorium calculated. Having established by the physico-chemical methods that the formula for thorium ferrocyanide is ThFe(CN)6, under all conditions, it has now become possible to estimate thorium volumetrically by the ferrocyanide method.

Volumetric studies in oxidation-reduction reactions: Reduction with ferrous ethylenediamine sulphate ceric sulphate method

Ferrous ethylenediamine sulphate has been used as a reducing agent in acid medium for the indirect volumetric estimations of potassium chlorate, potassium bromate, potassium metaperiodate, potassium dichromate, potassium ferricyanide, potassium permanganate, potassium persulphate, hydrogen peroxide and ceric sulphate. The excess of ferrous ethylenediamine sulphate added to each of the substances in acid medium was titrated with standard ceric sulphate solution using ferroin as an indicator.

Cerimetric determination of hypophosphite

AbstractA rapid method for the cerimetric determination of hypophosphite has been worked out, using silver salt as a catalyst. An excess of standard ceric sulphate solution is added to a solution containing hypophosphite acidified with sulphuric acid, and subsequently 2 ml of a 5% solution of Ag2SO4 in conc. sulphuric acid. The mixture is kept at the temperature of a boiling water bath for 20 minutes, and the unreacted eerie sulphate is determined with ferrous ammonium sulphate, after the mixture has been cooled.

Estimation of oxalic acid by photochemical oxidation with ceric sulphate

1. A new method has now been developed for the estimation of oxalic acid. The method consists in exposing a measured volume of the oxalic acid solution with a known excess of ceric sulphate solution to sunlight or to the light from a 1000 watt tungsten filament lamp for a short time (for 5 minutes to bright tropical sunlight and for 15 minutes under the light from a 1000 watt tungsten filament lamp). Then the excess of unreacted ceric sulphate is estimated by titration with standard Mohrs salt solution. 2. The method is applicable even in the presence of formic acid. High concentrations of formic acid show a slight error (0.5 to 1.0 percent) in experiments with sunlight, while no error is introduced in the experiments with the light of a 1000 watt tungsten filament lamp.

Cerate oxidimetry : Oxidation of formic, glycolic, malic, malonic and tartaric acids

1. Contrary to the observations of earlier workers, it has been shown that formic acid can be quantitatively oxidixed by ceric sulphate in the presence of concentrated sulphuric acid. 2. Tartaric, malonic, malic and glycolic acids can also be oxidized completely to carbon dioxide and water by the following general procedure : to a known amount of the organic acid is added ceric sulphate (excess) solution in dilute sulphuric acid and the mixed solution refluxed for ten to fifteen minutes. Concentrated sulphuric acid (double the volume of the reaction mixture) is then added taking care that formic acid is not lost during the addition, and the mixture again refluxed for 45 to 50 minutes. The excess ceric sulphate is determined by titrating against ferrous ammonium sulphate. 3. The complete oxidation of the above acids provides satisfactory methods for their quantitative estimation.

Rate of Dissolution of Silver in Aqueous Ceric Sulfate Solutions

The dissolution of silver and copper in ceric sulfate is diffusion controlled, in contrast to the dissolution in ferric sulfate solutions, which is desorption controlled. This is thought to be due to a greater heat of reaction which supplies sufficient energy for immediate desorption of ions produced in the course of reaction.By analogy with silver, reactions between oxidants and metals with small differences in standard oxidation potential should be desorption controlled. Reactions between oxidants and metals with large potential differences should be diffusion controlled.

The micro determination of blood sugar by ceric sulfate titration

A procedure for analysis of glucose solutions and blood is given. It involves the use of ferricyanide as an oxidizing agent and the titration of the ferrocyanide produced with standard ceric sulfate solution. The method requires far less standardization than is customary, and gives a constant factor relating glucose to ceric sulfate utilized. It is shown that the method gives about the same values for blood glucose as other commonly-used methods, but has the advantage of a greater rapidity and reproducibility as well as an easier technique.

Photochemical Reduction with X-Rays and Effects of Addition Agents

Ceric sulfate solution was reduced by exposure to x-radiation. In order to follow this reaction a very accurate method was developed for the determination of ceric sulfate in dilute solutions by the use of orthophenanthroline indicator. The amount of reduction of ceric sulfate by x-rays was found to be practically independent of concentration. Reduction was shown to be directly proportional to time of exposure up to 50 percent and slightly less efficient beyond that point. Silver perchlorate and silver nitrate decreased the amount of reduction of ceric sulfate by x-rays. Mercuric nitrate and acetic acid increased the amount of reduction caused by x-rays. Curves are also presented to show the effect of changing the concentration of these addition agents. Indications are that the mercuric nitrate was truly a catalyst to the reduction of ceric sulfate by x-rays and that the acetic acid increased the amount of reduction by direct action on the ceric sulfate under the influence of x-rays. Perchloric and nitric acids increased the reduction of ceric sulfate appreciably but not to as great an extent as did Hg(NO3)2. Sodium nitrate, perchlorate and sulfate showed no effect. Various organic substances were tried and found to increase the reduction by varying amounts. Experiments were carried out with various combinations of the catalysts and inhibitors to determine their relative efficiencies. The reduction of potassium permanganate by x-rays proceeded to manganese dioxide for low acid concentrations and to manganous ion at higher acidity. The reaction was greater than for ceric sulfate but not as nearly proportional to dosage. The effect of addition agents was similar to that for ceric sulfate. X-rays did not produce the same reaction in solutions of uranyl sulfate-oxalic acid as does ultraviolet radiation. Solutions of potassium iodate were reduced by x-rays but to a less degree than ceric sulfate or potassium permanganate. Hydrogen peroxide was formed in samples during radiation but did not effect the potassium iodate. Solutions of potassium bromate were not reduced by x-rays but even larger amounts of hydrogen peroxide were formed. Calculations were made for: ions reduced per r unit absorbed, r units necessary for reduction of one equivalent, ions reduced per ion pair formed by x-rays, and calories of absorbed energy necessary for reduction of one equivalent, by two independent methods. A mechanism was proposed for the formation of hydrogen peroxide by x-rays in the presence of dissolved oxygen.

The volumetric determination of nitrites by means of ceric sulphate solution

The volumetric determination of nitrites by means of ceric sulphate solution

Victoria Blue BX as Internal Indicator in Ceriometry

Several internal oxidation-reduction indicators have been proposed for titrations with standard solutions of potassium bichromate and ceric sulfate (1, 2). Some of those which are applicable with potassium bichromate cannot be used with ceric sulfate solutions because of the high oxidation-reduction potential of the latter. Hence it was thought desirable to continue the search for other indicators of high oxidation-reduction potential. Victoria blue BX,* a diphenylnaphthylmethane derivative manufactured by the Du Pont Company, has a more pronounced color change than any indicator we have studied, going from sky blue to a rather bright pink, which fades at once to a light pink. Although it is not a reversible indicator, the color change at the end point is exceptionally rapid and sharp. Overstepped end points can be redetermined by adding standard ferrous solution and a few more drops of indicator solution. Like ortho-phenanthroline, Victoria blue BX does not give a satisfactory color change when the stannous chloride method of reduction has been used. It serves admirably, however, when the iron has been reduced with cadmium, aluminum or zinc. An end point correction of 0.02 ml. should be made for accurate analysis, although for an accuracy of 0.20 per cent this correction is unnecessary when the usual volume of standard solution is used. The correction does not vary with volume within large limits. The end point may be approached at any reasonable rate. Nearness to the end point is indicated first by a slight fading of the blue solution to a clear sky-blue, and a few tenths of a milliliter before the end point is reached, a red spot can be seen for an instant as each drop of standard solution is added. At the end point as little as 0.02 ml. of 0.1 molar cerie sulfate solution will easily produce the entire color change. As a standard oxidizing solution, ceric sulfate has several advantages over potassium permanganate and potassium bichromate, but some disadvantages also. The first cost is considerably greater. Our standard solutions of ceric salts have not become constant in less than five or six weeks. During this period a precipitate slowly settles out. A solution made up with conductivity water in place of ordinary distilled water showed the same tendency. Cooling does not seem to hasten the separation.