With Methyl Orange

Another titration is performed with methyl orange, methyl orange-indigo carmine or bromophenol blue as indicator. Let the volume of acid be V mL. 

Primarily the sum of carbonate, bicarbonate and hydrate ions in water, but phosphate, silicate etc. may also contribute partially to alkalinity. Normally expressed as ppm (mg/1) CaC03. Phenolphthalein alkalinity (P Aik.) is that portion of alkalinity titrated with acid to pH 8.2 end-point, while total alkalinity (T Aik. or M Aik.) is that titrated with methyl orange indicator to pH 4.2 endpoint. 

A method suitable for quantification of the functional class of bis(ethanol)amine antistatics, which lack UV chromophores, consists of reaction with methyl orange [53]. Atmer 163 (alkyl-diethanol amine) has been determined as a yellow complex at 415 nm after interaction with a bromophenol/cresole mixture [64]. Hilton [65] coupled extracted phenolic antioxidants with diazotised p-nitroaniline in strongly acidic medium and carried out identification on the basis of the visible absorption spectrum in alkaline solution. The antioxidant Nonox Cl in... 

The determination of nitrogen in the pure product was performed by the usual method of slow distillation with excess of dilute sodium hydroxide solution, the evolved ammonia being collected, during 4 hr. distillation, in standard acid, and determined by titration as usual, with methyl orange as indicator. The yield of ammonia corresponded to 18-19 per cent of nitrogen in this sample. Calculated for FCH2CONH, N= 18-18 per cent. The standard fiuoroacetamide was therefore 100 per cent pure. 

At this juncture, add methyl orange solution and proceed ahead with the titration until a persistant pink colour is produced. Each millilitre of 1 N sulphuric acid is equivalent to 0.040 g (or 40 mg) of total alkali, calculated as NaOH and each millilitre of acid consumed in the titration with methyl orange is equivalent to 0.106 g of Na2C03. 

Subject the solution obtained to dialysis and treat the washing water first with phenolphthalein and then with methyl orange. Pour the solution into a number of test tubes and add to them 1 N solutions of salts of mono-, di-, and trivalent cations, respectively. What is observed Explain the occurring processes. 

Sphingosine bases are usually isolated from glycosphingolipids by treatment with methanolic HC1 containing some water,148 and characterized, in the form of the free bases or their 2,4-dinitrophenyl (DNP) derivatives,149 151 by t.l.c. For quantitative determination of bases, a colorimetric procedure is used, based on color formation of the base with Methyl Orange.152 The composition of the sphingosine bases, as their Me3Si derivatives, is determined by g.l.c. and g.l.c.-m.s.,148,153,154 as well as by using for this purpose... 

Allow all the gas to escape into the atmosphere. Remove the cover and wash it with distd w into a 25ml volumetric flask with the aid of a funnel. Transfer (quantitatively) the contents of the bomb into the same flask and fill it with w to mark. After mixing the contents, pipet a 50ml aliquot into a tall beaker and titrate with std HC1 soln using successively two indicators, first phpht and then methyl orange Calculation. If reading with phpht indicator is n and with methyl orange n , then... 

The lithium carbonate concentration was measured by acidimetric titration with methyl orange indicator. The calcium sulfate and calcium hydroxide concentrations were determined by titration with disodium dihydrogen Versenate [the disodium salt of (ethylenedinitrilo) tetraacetic acid], with added magnesium chloride. A buffer of ammonium chloride in ammonium hydroxide was employed. The indicator was Erio-chrome Black T. A special high purity calcium carbonate in hydrochloric acid was used as a standard. Because of the high concentration of sodium sulfate it was con-... 

E. Blanc calculated for the ionization of constants of phosphorous acid Ki=0 05, and isT2—2 4 XlO-5. I. M. Kolthoff found that the first ionization constant Ky increases from 0 016 in 0 001 Jkf-soln. to 0 062 in O lJf-soln. and the second ionization constant K2, calculated from the H -ion cone, of mixtures of a secondary phosphite with hydrochloric acid is O O07 at 18°. The first stage of phosphorous acid titration may be conducted with methyl-orange as indicator using a comparison soln. with ps—Z 85. A sharp end-point for the second stage is obtained with thymolphthalein as indicator. For the anodic oxidation of the phosphites, vide infra, perphosphates. P. Pascal studied the magnetic properties. 

The first experimental application of this concept was reported in the seminal work of Dickey, who, in 1949, stated that silica, adsorbed with methyl orange, showed preferential absorption properties towards the same structure. Dickey, hypothesising the mechanism with which the specific adsorption was generated, invoked Pauling s antibody formation theory This mechanism is the same as that proposed by Pauling for the formation of antibodies with use of antigen molecules as a template. [4],... 

With one indicator the pH can only be determined very roughly. For instance, when a solution turns red after methyl orange has been added, the pH is < 3.1. By combining a number of indicators it is possible to determine the pH more accurately. When a solution with methyl orange is yellow and also yellow with bromothymol blue, then the following holds 4.4 < pH < 6.0. 

The dish containing the solution of fluoboric acid is again placed in an ice bath, and 5N potassium hydroxide solution is added slowly, with stirring, until a test portion gives an alkaline reaction with methyl orange. The solution is kept in an ice bath until it is chilled and the crystals of potassium fluoborate have settled. 

Hirai et al. [18] found that /LCD forms 1 1 complexes with Methyl Orange and Congo Red in water, whereas y-CD forms 1 2 complex with Methyl Orange and 1 1 complex with Congo Red. Induced circular dichroism of the dyes was studied allowing determination of stability constants. 

At a temperature of 78° C. the velocity constant whether referred to a unimolecular or a bimolecular reaction diminished with time after an hour rather less than three-quarters of the original metaphosphate remains.6 The product is mainly orthophosphate, as was proved by titration with methyl orange and phenolphthalein, although small quantities of pyrophosphate were formed by a side reaction. The pyro-acid was determined by titration to bromophenol blue in the presence of zinc sulphate, which leads to a complete precipitation of pyrophosphate, the ortho-acid being unaffected, thus... 

Metaphosphoric Acid may be titrated with methyl orange, etc. irrespective of its progressive hydration (p. 175). The phenolphthalein titre, however, varies with time (see p. 176). 

This approximate relationship between the titration exponent and pAin is applicable to phenolphthalein and to many of the sulfonephthalein indicators introduced by Clark and Lubs (sec Table LXIV, page 364). If the darker color is obtained in acid solution, as is the case with methyl orange and methyl red, then it is approximately true that... 

It is possible by suitable selection of indicators to titrate separately a strong acid and a weak acid or a strong base and a weak base in a mixture of the two. Let us consider, for example, a solution of sodium hydroxide and ammonium hydroxide. If strong acid is added until the pH is 11.1, which is that of 0.1 N ammonium hydroxide solution, the strong base will be within 1% of neutralization (Fig. 20-3). Hence by using alizarine yellow [pK 11) as indicator the concentration of strong base can be determined, and then by a second titration with methyl orange the concentration of ammonium hydroxide can be found. 

Gels prepared with Methyl orange Ethyl orange Propyl orange Butyl orange... 

Folkers and coworkers - found that when sufliciently pure concentrates of streptomycin were treated with methyl orange (the sodium salt of helianthine) a crystalline salt was formed with the sulfonic acid group of this dye. On recrystallization from aqueous methanol, pure streptomycin helianthate was obtained. The helianthate could be converted to streptomycin hydrochloride, sulfate or any other suitable salt for chemical or therapeutic purposes. All of these salts with the common inorganic acids are amorphous. They - also obtained a crystalline salt of streptomycin and p-(2-hydroxy-l-napthylazo)-benzenesulfonic acid from streptomycin hydrochloride and the azo dye Orange II. Streptomycin helianthate was converted directly into a crystalline streptomycin trihydrochloride-calcium chloride double salt. The chemistry of streptomycin was thus put on a crystalline basis. 

A sample of rainwater tested with methyl orange results in a yellow color, and the addition of methyl red to a fresh sample of the same water results in a red color. What is the pH of the sample ... 

The procedure described in Problem 14-8 was used to determine pH with methyl orange as the indicator. The concentration ratio of the acid to base form of the indicator was 1.64. Calculate the pH of the solution. 

A series of acid-base indicators can be used to estimate the pH of an unknown solution. Use the values given in Table 19-4 to determine the possible range of pH values of the following solution. The solution was colorless with phe-nolphthalein, yellow with methyl orange, and yellow with methyl red. 

PithaJ and Teruhiko H. Effect of Ethanol on Formation of Inclusion Complexes of Hydroxypropyl Cyclodextrins with Testosterone or with Methyl Orange./rat JPharm 1992 243-251. 

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