Titration, iodometric

In addition to those indicators listed in Table 8.26, there are indicators for bromometric and iodometric titrations ... 

Specific reagents for iodometric titrations Organic solvents such as CCI4, CHCI3... 

As a strong reduciug agent, hydraziue can be deterrniued quantitatively usiug a variety of oxidants. Most convenient, perhaps, is an iodometric titration (140) ... 

Thus the quantitative oxidation of 8203 " by I2 to form tetrathionate and iodide is the basis for the iodometric titrations in volumetric analysis... 

The direct iodometric titration method (sometimes termed iodimetry) refers to titrations with a standard solution of iodine. The indirect iodometric titration method (sometimes termed iodometry) deals with the titration of iodine liberated in chemical reactions. The normal reduction potential of the reversible system ... 

Only freshly prepared starch solution should be used. Two millilitres of a 1 per cent solution per 100 mL of the solution to be titrated is a satisfactory amount the same volume of starch solution should always be added in a titration. In the titration of iodine, starch must not be added until just before the end point is reached. Apart from the fact that the fading of the iodine colour is a good indication of the approach at the end point, if the starch solution is added when the iodine concentration is high, some iodine may remain adsorbed even at the end point. The indicator blank is negligibly small in iodimetric and iodometric titrations of 0.05M solutions with more dilute solutions, it must be determined in a liquid having the same composition as the solution titrated has at the end point. 

Unique methods based on new principles have been developed within the past 10 years. Threonine (27,28,249) is oxidized by lead tetraacetate or periodic acid to acetaldehyde, which is determined by photometric analysis of its p-hydroxydiphenyl complex or iodometric titration of its combined bisulfite. Serine is oxidized similarly to formaldehyde, which is determined gravimetrically (207) as its dimedon (5,5-dimethyldihydro-resorcinol) derivative or photometric analysis (31) of the complex formed with Eegriwe s reagent (l,8-dihydroxynaphthalene-3,5-disulfonic acid). It appears that the data obtained for threonine and serine in various proteins by these oxidation procedures are reasonably accurate. [Block and Bolling (26) have given data on the threonine and serine content of various proteins. ]... 

Because aqueous solutions of hydroxylamine-O-sulfonic acid are not very stable, it is very important to use freshly prepared solutions. The purity of hydroxylamine-O-sulfonic acid should be checked by iodometric titration. If it is less than 85-... 

After all the peracetic acid has been added, the reaction mixture is diluted with 80 ml. of water and heated from 35° to 100° over a 20-minute period (Note 2). It is then kept at 100° for 45 minutes. The flask is cooled to 0-5° in an ice bath, and the solid iodoxybenzene is collected on a Buchner funnel and air-dried with suction for 1 hour. Additional material is obtained by concentrating the filtrate to one-fourth of its volume (Caution Note 3). The two crops of crude iodoxybenzene are combined and dried overnight in a desiccator weight 19.6-20.5 g. m.p. 230° Caution Explodes ). Iodometric titration 3 shows the purity to be about 94% (Note 4). 

Purification of the crude iodoxybenzene is effected by grinding it to a powder in a mortar, macerating it with 70 ml. of chloroform, and separating the solid by filtration. The chloroform extraction is repeated and the solid is dried weight 17-19 g. (72-80%) purity 99.0-99.9% by iodometric titration.3... 

Iodine was determined by an iodometric titration adapted from White and Secor.(3) Instead of the normal Carius combustion, iodide was separated from the samples either by slurrying in 6M NaOH, or by stirring the sample with liquid sodium-potassium (NaK) alloy, followed by dissolving excess NaK in ethanol. Precipitated plutonium hydroxides were filtered. Iodine was determined in the filtrate by bromine oxidation to iodate in an acetate buffer solution, destruction of the excess bromine with formic acid, acidifying with SO, addition of excess KI solution, and titrating the liberated iodine with standard sodium thiosulfate. The precision of the iodine determination is estimated to be about 5% of the measured value, principally due to incomplete extraction of iodine from the sample. 

Absorb in an impinger containing a standardized solution of iodine and potassium iodide titrate with standard sodium thiosulfate solution. Iodometric titration No data NR EPA 1978... 

Aspirate through ammoniacal cadmium chloride strip sulfur dioxide by aeration dissolve cadmium sulfide precipitate in concentrated HC1 titrate with iodine using a starch indicator. Iodometric titration 0.7 qg/L NR EPA 1978... 

The ready separation of the hexachloroantimonate salts of various cation radicals is possible owing to their insolubility in diethyl ether (or hexane) under conditions in which the reduced antimony(III) chloride is highly soluble. In the case of EA+ SbClg", the isolated product is quite pure as determined by iodometric titration. However in many other cases, the Lewis acid SbCl5 effects... 

The practical application of these observations is to minimise the effect of iodate by rapidly carrying out the iodometric titration of chlorine residual in seawater at pH 4. Moreover, if desired, a titration correction curve can be generated using iodate at the specific concentration of iodide in the sample in question, as there appears to be a complete conversion of seawater iodide to iodate in the presence of excess chlorine. 

The concentration of copper in a sample may be determined by using an iodometric titration or by atomic absorption spectrometry. In each of the following examples, calculate the cost of the assay (assume that the charge for the analyst s time is 50 per hour) ... 

D 2547 24 0.05-1.1 g Pb/L Mineralization of organic lead, precipitation of PbCr04, redissolution in HCl/NaCl solution, addition of KI and iodometric titration of liberated I2. 

A. Trichloramine. A mixture of 600 ml. of water (Note 2), 900 ml. of methylene chloride (Note 3), and 270 g. (1.32 moles) of calcium hypochlorite (Note 4) is cooled to 0-10° in a 3-1., three-necked, vented flask equipped with a stirrer, a thermometer, and a dropping funnel. A solution of 66.0 g. (1.23 moles) of ammonium chloride in 150 ml. of concentrated hydrochloric acid and 450 ml. of water is added dropwise with stirring over a 1-hour period at 0-10°. After an additional 20 minutes of stirring, the organic layer is separated, washed with three 200-ml. portions of cold water, and dried over anhydrous sodium sulfate. The yellow solution is filtered, and the trichloramine concentration is determined by iodometric titration (Note 5). 

All monomers, surfactants, buffers, and chain transfer agents were used as provided. Water was deionized. Purchased organic peroxides were all reagent grade. Organic peroxides were prepared from the reaction products of acyl chlorides and sodium peroxide. Activity was determined by iodometric titration. 

The products of perfluorination are both white, very different from the original black hydrocarbon polymers. Both materials are moisture-sensitive powders and slowly degraded by atmospheric moisture, 6 more quickly than 5. The materials oxidize iodide ion to iodine owing to the presence of the N—F moiety. A series of iodometric titrations showed that 6 required twice the number of equivalents of titrant as did 5. This result supports the proposed structures 6 having twice as many N—F moieties as 5. 

Iodometric ozone analysis, 17 811 Iodometric titration, 13 588 Iodonium salts, 15 166... 

Iodometric titration, 50, 17 Ion-exchange resin, Amberlite IR-120, cyclization with,... 

Kupec et al. [180] determined total sulphur in sludge by a method involving magnesium reduction in which the sample is heated with magnesium powder to convert all sulphur compounds into magnesium sulphide. The magnesium sulphide is treated with sulphuric acid and the evolved hydrogen sulphide determined by iodometric titration. 

What is the basic difference between iodimetric and iodometric titrations Explain with the help of equations involved in such typical titrations. 

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