Sodium hypochlorite as volumetric reagent

Summary Sodium hypochlorite solution has been used as an oxidising agent for the volumetric determination of semicarbazide hydrochloride, phenylhydrazine hydrochloride, benzalazine, benzalsemicarbazone, o-chlorobenzalsemicarbazone, acetonesemicarbazone, aminoguanidine hydrochloride, thiosemicarbazide, o-hydroxy benzalsemicarbazone, 3,4-methylenedioxy benzalsemicarbazone and p-methoxy benzalsemicarbazone, using iodine monochloride as catalyst and preoxidizer. During these titrations normality of the solution with respect to hydrochloric acid has been kept between 2.0 N and 3.5 N. Chloroform is used as an indicator. It is coloured pink due to the liberation of iodine during the titration and becomes very pale yellow at the end-point owing to the formation of iodine monochloride. Each hydrazino group in these compounds is oxidised quantitatively with a four-electron change to nitrogen with sodium hypochlorite as an oxidant in hydrochloric acid solution.     

Volumetric studies in oxidation-reduction reactions: Oxidation with chloramine-t. iodine monochloride method

Chloramine-T has been used as an oxidizing agent in hydrochloric acid medium' for the volumetric estimations of potassium iodide, hydrazine sulphate, arscnious oxide, stannous chloride, mercurous chloride, tartar-emetic, potassium thiocyanate and ferrous ammonium sulphate, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride.     

Diethylenetetra-ammonium sulphatocerate as volumetric reagent : Determination of organic derivatives of hydrazine by the iodine monochloride method

Diethylenetetra-ammonium sulphatocerate has been used as an oxidising agent in hydrochloric acid medium for the volumetric determination of semicarbazide hydrochloride, benzalazine, benzalsemicarbazone, aminoguanidme hydrochloride, chloralhydrazinc, P-methoxybcnzalsemicarbazonc, o-chlorobenzalsemicarbazone and acetonesemicarbazone, using iodine monochloride as a catalyst and preoxidiser Chloroform was used as an indicator. It was coloured violet owing to the liberation of iodine during the titration and became very pale yellow at the end-point owing to the formation of iodine monochloride Each hydrazino group in these compounds was oxidised quantitatively with a four-electron change to nitrogen with diethylenetctra-ammonium sulphatocerate as an Oxidant in hydrochloric acid solution.     

Studies in oxidation-reduction reactions: Oxidation with chloramine-b,iodine monochloride method

Chloramine-B has been used as an oxidizing agent in hydrochloric acid medium for the volumetric estimations of potassium iodide, arsenious oxide, tartar-emetic, mercurous chloride, stannous chloride, potassium thiocyanate, ferrous ammonium sulphate, hydrazine sulphate and hydroquinone, using iodine monochloride as a catalyst and pre-oxidizer. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point because of the formation of iodine monochloride.     

Sodium meta-vanadate as volumetric reagent : Iodine monochloride method

Sodium meta-vanadate has been used as an oxidising agent in hydrochloric acid medium for the volumetric estimations of potassium iodide, sodium arsenite, mercurous chloride, potassium thiocyanate, sodium sulphite, sodium bisulphite, sodium thiosulphate, ferrous sulphate and hydrazine sulphate, using iodine monochloride as a catalyst and preoxidiser. Chloroform is used as an indicator. It is coloured pink due to the liberation, of iodine during the titration and becomes light pale yellow at the end-point due to the formation of iodine monochloride.     

Volumetric studies in oxidation-reduction reactions : Oxidation with sodium hypochlorite iodine monochloride method

Alkaline sodium hypochlorite was used as an oxidant to determine arsenious oxide, hydrazine sulphate, ferrous ammonium sulphate, stannous chloride, sodium sulphite, potassium iodide, mercurous chloride, thallous chloride and tartar emetic, by a volumetric method, using iodine monochloride as catalyst and preoxidizer. During these titrations, the normality of the solution with respect to hydrochloric acid was kept between 5N and 7N, Chloroform was used as an indicator. Its pink colour due to the liberation of iodine during the titration turns very pale yellow at the end-point because of the formation of iodine monochloride     

Sodium metavanadate as volumetric reagent : Determination of organic derivatives of hydrazine,iodine monochloride method

Sodium metavanadate has been used as an oxidising agent in hydrochloric acid medium for the volumetric determination of semicarbazide hydrochloride, benzalazine, benzalsemicarbazone, aminoguanidine hydrochloride, o-hydroxybenzalsemicarbazone, p-methoxybenzalsemicarbazone, chloralhydrazine, o-chlorobenzalsemicarbazone and ethyl methyl ketone semicarbazone, using 10-dine monochloride as a catalyst and preoxidiser Chloroform was used as an indicator. It was coloured violet due to the liberation of iodine during the titration and became light pale yellow at the end-point owing to the formation of iodine monochloride Eachhydrazino group in these compounds was oxidised quantitatively with a four-electron change to nitrogen with sodium metavanadate as an oxidant in hydrochloric acid solution.     

Studies in oxidation-reduction reactions: Oxidation with chloramine-b indirect determinations

Chloramine-B has been used as an oxidizing agent in hydrochloric acid medium for the indirect volumetric estimations of hydrogen peroxide, lead dioxide, manganese dioxide, selenium dioxide, sodium formate, sodium sulphide, sodium metavanadate, potassium iodate and copper sulphate using iodine monochloride as a catalyst and pre-oxidiser. Chloroform is used as an indicator. It is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point because of the formation of iodine monochloride.     

Potassium persulphate as volumetric reagent

Summary Potassium persulphate has been used as volumetric reagent for the direct determination of hydrazine sulphate, phenyl hydrazine hydrochloride, semicarbazide hydrochloride, thiosemicarbazide, acetone semicarbazone, benzal semicarbazone, benzalazine, aminoguanidine hydrochloride, 4-phenyl semicarbazide hydrochloride, ethylmethyl ketone semicarbazone and 4-hydroxy-3-methoxy benzal semicarbazone in hydrochlorid acid medium at room temperature, using iodine monochloride as a catalyst and preoxidiser. Chloroform was used as an indicator. It was coloured violet owing to the liberation of iodine during the titration and became very pale yellow at the end-point due to the formation of iodine monochloride. Normality of the solution with respect to hydrochloric acid was kept between 6.0 and 7.5 N in these redox titrations.     

Use of brucine as an oxidation-reduction indicator in cerimetry

Summary Brucine has been found to work satisfactorily as an inside indicator in the titration of molybdenum(V) and hydroquinone with ceric sulphate. It does not give a good indication of the end point in the titration of arsenic(III) in sulphuric acid medium, using osmium tetroxide as a catalyst or in hydrochloric acid medium using iodine monochloride as a catalyst. Brucine cannot also be used in the titration or uranium(IV) with ceric sulphate. A 0.1 per cent solution of brucine in 2 N–3 N acetic acid has been found to be stable for nine months without showing any discoloration.     

Sodium hypochlorite as volumetric reagent

Summary In presence of 5 N to 6 N hydrochloric acid, ferrous ethylenediamine sulphate was used as a reducing agent to determine indirectly potassium chlorate, potassium bromate, potassium metaperiodate, potassium dichromate, potassium ferricyanide, potassium permanganate, potassium persulphate, hydrogen peroxide, ceric sulphate and chloramine-T. An excess of ferrous ethylenediamine sulphate added to each of the substances in the acid medium was titrated with a standard solution of sodium hypochlorite. Iodine monochloride was used as catalyst and preoxidizer and chloroform was used as an indicator. Chloroform was coloured violet owing to the liberation of iodine during the titration and became very pale yellow at the end-point because of the formation of iodine monochloride.Part I: See Z. analyt. Chem. 160, 429 (1958).     

Sodium meta-vanadate as volumetric reagent : Iodine monochloride method (Indirect determinatios)

Sodium meta-vanadate has been used as an oxidizing agent in hydrochloric acid medium for the indirect volumetric determination of hydrogen peroxide, lead dioxide, manganese dioxide, selenium dioxide, potassium persulphate, copper sulphate, sodium formate and sodium sulphide using iodine monochloride as a catalyst, pre-oxidizer and an indicator. Chloroform is coloured pink owing to the liberation of iodine during the titration and becomes light pale yellow at the end-point owing to the formation of iodine monochloride.     

Diethylenetetra-ammonium sulphatocerate as volumetric reagent: Iodine monochloride method

The method of preparation of diethylenetetra-ammoniuin sulphatocerate is described. This substance has been used as an oxidant to determine potassium iodide, ferrous ammonium sulphate, arsenious oxide, stannous chloride, hydrazinc sulphate, thallous chloride. hydroquinone and potassium ferrocyanide by a volumetric method, using iodine inonochloride as catalyst and preoxidizer. During these titrations, normality of the solution with respect to hydrochloric acid has been kept at about 6N. Chloroform is used as an indicator. It is 'coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride.     

Sodium meta-vanadate as volumetric reagent: Iodine monochloride method

In hydrochloric acid medium sodium meta-vanadate was used as a volumetric reagent for the determination of copper, zinc, cobalt, mercury, and lead. Cu⁺², Zn⁺² and Co⁺²were precipitated as complex mercurythiocyanates, Hg⁺² as mercuric zinc thiocyanate and Pb⁺² as Iodide. The thiocyanates were dissolved in concentrated hydrochloric acid and titrated against standard sodium meta-vanadate solution in the presence of iodine monochloride as a pie.oxidizer and catalyst. In titration of the iodide against the meta-vanadate. it was not necessary to add iodine monochloride to the titrant because it is formed during the titration. Chloroform was used as an indicator. It was pink owing to the liberation of iodine during the titration and became pale yellow at the end-point because of the formation of iodine monochlonde.     

Cerimetric determination of uranium Use of triphenylmethane dyes as internal indicators

The use of the triphenylmethane dyes (erioglaucine, eriogreen, and xylene cynol FF) as internal indicators in the cerimetric titration of uranium^IV has been investigated. The titration is possible in the cold with sufficient rapidity and accuracy, the indicator colour change appearing sharply at the equivalence point. The indicator reactions are rapid and reversible within a wide range of acidity, from 0.5N to 8.0N, unlike other indicators, e.g. diphenylbenzidine, -phenylanth-ranilic acid or ferroïn, which require specified conditions for their proper functioning. These indicators can also beused for titration of uranium^IV with eerie ammonium nitrate in perchloric acid medium (but not in nitric acid medium).     

Volumetric studies in oxidation-reduction reactions: Oxidation with chloramine-t. indirect determinations

Chloramine-T has been used as an oxidizing agent in hydrochloric acid medium for the indirect volumetric determination of hydrogen peroxide, lead dioxide, selenium dioxide, sodium formate, potassium meta-periodate, potassium permanganate and potassium dichromate using iodine monochloride as a catalyst, prcoxidizer and an indicator. Chloroform is coloured pink owing to the liberation of iodine during the titration and becomes very pale yellow at the end-point because of the formation of iodine monochloride.     

Diethylenetetra-ammonium sulphatocerate as volumetric reagent: Iodine monochloride method. Indirect determinations

In presence of 4N to N hydrochloric acid, diethylenetetra-ammnonium sulphatocerate was used as a volumetric reagent to determine indirectly potassium iodate, potassium metaperiodate, potassium dichromate, potassium bromate, ceric sulphate, hydrogen peroxide, lead dioxide and chloramine-B by the iodine monochloride method. An excess of potassium iodide added to each of the substances in the acid medium was, titrated back with a standard solution of diethylene-tetra-ammonium suphatocerate. Chloroform was used as an indicator. It was coloured violet owing to the liberation of iodine during the titralion and became very pale yellow at the end-point because of the formation of iodine monochloride.     

Simple conditions for the use of ferroin indicator in cerimetric titrations of antimony(III) alone and in mixtures with arsenic(III)

The titration of antimony(III) with cerium(V) sulphate in the presence of ferroin indicator at room temperature is entirely satisfactory in media consisting of 50% ($\text{v}\text{v}$) acetic acid and 1–3 M hydrochloric acid. In the absence of acetic acid, ferroin reacts with the antimony(V) formed in the very early stages, to give a sparingly soluble red complex, which remains in suspension and resists oxidation by cerium(IV). This titration provides a rational method for sequential visual titrations of antimony(III) and arsenic(III). The composition of the ferroin-antimony(V) complex is discussed. Titrations of antimony(III) in 0.5–1 M sulphuric acid medium do not require acetic acid but need iodine monochloride catalyst.     

Dichrometric determination of thallium (I)

Summary A dichrometric procedure has now been developed for the direct volumetric titration of thallium(I), to an iodine monochloride end point. The concentration of the hydrochloric acid must be at least 7.5 N at the end point.     

A new volumetric method for the determination of molybdenum(VI)

Summary A new volumetric method has been developed for the determination of molybdenum(VI). The method consists in the reduction of molybdenum(VI) by heating with a slight excess of hydrazine sulphate in 1 to 2 M hydrochloric acid medium for ten minutes on a water bath. The mixture is cooled and the molybdenum(V) obtained determined by titration with a standard solution of ceric sulphate at an overall acidity of 4 N hydrochloric acid, using diphenyl benzidine as indicator and adding 5 ml of syrupy phosphoric acid for 50 ml of the mixture. Alternately the molybdenum(V) can be titrated with a standard solution of ceric sulphate at an overall acidity of 3 N hydrochloric acid using ferroin as indicator and adding 5 ml of syrupy phosphoric acid for 50 ml of the titration mixture. The molybdenum(V) can also be titrated with a standard solution of sodium vanadate in 8 N sulphuric acid medium, using N-phenyl anthranilic acid as indicator. Alternately, the titration with sodium vanadate can be made with diphenyl benzidine as indicator in 4 N acid medium, adding 5 ml of syrupy phosphoric acid and 1 ml of 1.0 M oxalic acid to catalyse the indicator action. The method now proposed is much more convenient than the methods currently available. It is simple because it does not require any costly chemicals or complicated apparatus. Furthermore, it has the advantages of great rapidity and excellent precision.