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Determination of NaOH, Na2CO3 and NaHCO3 in their mixtures by an electrometric non-compensating method.
1960
A’bs trac ts Set tion
A 117
sample, Vi = volume of base added up to point i, VI = volume of base needed to reach the equivalence point. Correction terms are derived from the Debye and Hilckel equation for any experimental Ki; the correction is equal to 1.011 (pi)” where ~_l~ F ionic strength at the point i obtained from:
The following values were found: benzene-sulfinic acid=1.84, p-toluene=1.99; p-bromo-benzene=1.89; p-chloro-benzene=1.81; m-nitro-benzene=l. 88; p-nitrobenzenez1.86. Ca. Cas. ELECTRODE TENSIONS IN FUSED SYSTEMS. V. CELLS WITH TRANSFERENCE. Kurt H. Stern. (Chemistry Dept. , University of Arkansas, Fayetteville, Ark. , U.S. A.) J. Phys. Chem., 63 (1959) ‘741. The cells (1) Cl,/Ag Cl, Na Cl/Cl,; (2) Cl,/Na Cl, KCl/Cl,; (3) Cl,/Ag Cl, KCl/C12 were found to exhibit zero tensions within experimental error (& 0.5 mV). The measured tensions of cells of this type, A,/M’A, M”A/A2, can be attributed to events at the liquid junction M’A, M”A. The tension is shown to be zero if the mobilities of M’ and M” are equal. D. S. Ru. [378] DETERMINATION OF NaOH, Na2C0a AND NaHC03 IN THEIR MIXTURES BY AN ELECTROMETRIC NON-COMPENSATING METHOD. S. K. Chirkov. (A.M. Gorky Ural State University, Sverdlovsk, U. S. S. R,) Zhur. Anal.Khim., 14 (1959) 370. The method described is a potentiometric titration in which a tungsten indicator electrode is coupled with a copper sulphate comparison electrode across a resistance of 5 kj and a sensitive galvanometer. The titration curves are similar to the usual potentiometric curves but the tension change is slower. The equivalencepoint is determined graphically and is at the intersection of 2 straight lines extended through the part of the curve corresponding to the tension change and the following part. This is different from the usual compensating potentiometric titration in which the equivalence-point corresponds to the inflection point of the curve. The method has been applied to titrations of NaOH, Na,COa, NaHCO,, mixtures of NaOH and NazCOa and Na2COa and NaHCQ. The titration curve of Na2COa contains 2 inflections corresponding to the neutralisation of COa2- to HC03 - and of HCO,- to H,O + CO,. The precision is f 0.5 to 1.0% depending on the sensitivity of the galvanometer, the resistance of the circuit and the precision with which the curves are drawn. ot. so. [3791 THE SUCCESSIVE DETERMINATION OF IRON, COPPER AND TITANIUM IN FERROTITANIUM BY A CHROMOMETRIC METHOD. A.I.Busev and Li Gyn. (M. V. Lomonosov State University, Moscow, U. S. 6. R.) Zavodskaya Lab. , 25 (1959) 3c. In studying the successive potentiometric determination of Fe, Cu and Ti with CrC12 solutions difficulties were encountered in the end-point indication with a Pt electrode. At tensions of the titrated solution (given by the concentration ratio
A’bs trac ts Set tion
A 117
sample, Vi = volume of base added up to point i, VI = volume of base needed to reach the equivalence point. Correction terms are derived from the Debye and Hilckel equation for any experimental Ki; the correction is equal to 1.011 (pi)” where ~_l~ F ionic strength at the point i obtained from:
The following values were found: benzene-sulfinic acid=1.84, p-toluene=1.99; p-bromo-benzene=1.89; p-chloro-benzene=1.81; m-nitro-benzene=l. 88; p-nitrobenzenez1.86. Ca. Cas. ELECTRODE TENSIONS IN FUSED SYSTEMS. V. CELLS WITH TRANSFERENCE. Kurt H. Stern. (Chemistry Dept. , University of Arkansas, Fayetteville, Ark. , U.S. A.) J. Phys. Chem., 63 (1959) ‘741. The cells (1) Cl,/Ag Cl, Na Cl/Cl,; (2) Cl,/Na Cl, KCl/Cl,; (3) Cl,/Ag Cl, KCl/C12 were found to exhibit zero tensions within experimental error (& 0.5 mV). The measured tensions of cells of this type, A,/M’A, M”A/A2, can be attributed to events at the liquid junction M’A, M”A. The tension is shown to be zero if the mobilities of M’ and M” are equal. D. S. Ru. [378] DETERMINATION OF NaOH, Na2C0a AND NaHC03 IN THEIR MIXTURES BY AN ELECTROMETRIC NON-COMPENSATING METHOD. S. K. Chirkov. (A.M. Gorky Ural State University, Sverdlovsk, U. S. S. R,) Zhur. Anal.Khim., 14 (1959) 370. The method described is a potentiometric titration in which a tungsten indicator electrode is coupled with a copper sulphate comparison electrode across a resistance of 5 kj and a sensitive galvanometer. The titration curves are similar to the usual potentiometric curves but the tension change is slower. The equivalencepoint is determined graphically and is at the intersection of 2 straight lines extended through the part of the curve corresponding to the tension change and the following part. This is different from the usual compensating potentiometric titration in which the equivalence-point corresponds to the inflection point of the curve. The method has been applied to titrations of NaOH, Na,COa, NaHCO,, mixtures of NaOH and NazCOa and Na2COa and NaHCQ. The titration curve of Na2COa contains 2 inflections corresponding to the neutralisation of COa2- to HC03 - and of HCO,- to H,O + CO,. The precision is f 0.5 to 1.0% depending on the sensitivity of the galvanometer, the resistance of the circuit and the precision with which the curves are drawn. ot. so. [3791 THE SUCCESSIVE DETERMINATION OF IRON, COPPER AND TITANIUM IN FERROTITANIUM BY A CHROMOMETRIC METHOD. A.I.Busev and Li Gyn. (M. V. Lomonosov State University, Moscow, U. S. 6. R.) Zavodskaya Lab. , 25 (1959) 3c. In studying the successive potentiometric determination of Fe, Cu and Ti with CrC12 solutions difficulties were encountered in the end-point indication with a Pt electrode. At tensions of the titrated solution (given by the concentration ratio