The theory of titration of polybasic acids. II. Conditions for the existence of inflexions near equivalence points

SD Hamann

doi:10.1071/ch9701749

The theory of titration of polybasic acids. II. Conditions for the existence of inflexions near equivalence points

Australian Journal of Chemistry ◽

10.1071/ch9701749 ◽

1970 ◽

Vol 23 (9) ◽

pp. 1749

Author(s):

SD Hamann

Keyword(s):

Activity Coefficients ◽

Acid Concentration ◽

Equivalence Point ◽

Titration Curves ◽

Finite Concentration

Calculations have been made of the conditions that are necessary for the existence of vertical equivalence point inflexions in the titration curves of dibasic, tribasic, and polybasic acids. Account has been taken of the effects of finite acid concentration, of finite concentration of the titrating base, of finite strength of the titrating base, and of activity coefficients. As a rule, each of these effects causes a flattening of the titration curves and the ultimate disappearance of inflexions.

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The hydrolysis of thioacetic, thiobenzoic, and three substituted thiobenzoic acids in perchloric and sulfuric acids

Canadian Journal of Chemistry ◽

10.1139/v78-156 ◽

1978 ◽

Vol 56 (7) ◽

pp. 935-940 ◽

Cited By ~ 3

Author(s):

John T. Edward ◽

Graeme Welch ◽

Sin Cheong Wong

Keyword(s):

Sulfuric Acid ◽

Activity Coefficients ◽

Acid Concentration ◽

Perchloric Acid ◽

Transition States ◽

Sulfuric Acid Concentration ◽

Thiobenzoic Acid ◽

The Difference ◽

Different Response ◽

Hydrolysis Of

The rates of hydrolysis of thioacetic, thiobenzoic, and three substituted thiobenzoic acids increase with concentration of solvent sulfuric or perchloric acid to a maximum in 30–40% acid and then decrease. Yates–McClelland r, Bunnett–Olsen [Formula: see text], and Hammett ρ parameters, and entropies of activation indicate an AAC2 mechanism over this range of acid concentrations. In acid concentrations above 50–60% the rates increase sharply and the same mechanistic criteria now indicate an AAc1 mechanism. The difference between the rate–acidity profile of thiobenzoic acid and that of ethyl thiolbenzoate can be explained by the different response of the activity coefficients of their transition states to increase in sulfuric acid concentration.

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Prediction of finite-concentration activity coefficients from a single g.l.c.-determined activity coefficient at infinite dilution

The Journal of Chemical Thermodynamics ◽

10.1016/0021-9614(75)90172-x ◽

1975 ◽

Vol 7 (4) ◽

pp. 353-357 ◽

Cited By ~ 5

Author(s):

T.M. Letcher ◽

G. Netherton

Keyword(s):

Activity Coefficient ◽

Activity Coefficients ◽

Infinite Dilution ◽

Finite Concentration

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Integral method for infinite dilution activity coefficients calculation

Canadian Journal of Chemistry ◽

10.1139/v92-205 ◽

1992 ◽

Vol 70 (6) ◽

pp. 1645-1649 ◽

Cited By ~ 7

Author(s):

A. C. Chialvo

Keyword(s):

Activity Coefficients ◽

Integral Method ◽

Infinite Dilution ◽

Binary Systems ◽

Experimental Dependence ◽

Data Sets ◽

Limiting Behavior ◽

Infinite Dilution Activity Coefficients ◽

Finite Concentration

An integral method to determine infinite dilution activity coefficients [Formula: see text] from data sets of finite concentration activity coefficients is proposed for binary systems. This method is based upon the integration of the experimental dependence of ln [Formula: see text] over different composition ranges. The limiting behavior of this function is analysed, in order to improve the precision of its integration. The accuracy of this method is demonstrated by the calculation of [Formula: see text] for several systems.

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The possibility of determining the activity coefficients of individual ions from acid-base titration data

Journal de Chimie Physique ◽

10.1051/jcp:1998330 ◽

1998 ◽

Vol 95 (7) ◽

pp. 1583-1605 ◽

Cited By ~ 2

Author(s):

I. Jano ◽

J. E. Hardcastle

Keyword(s):

Activity Coefficients ◽

Acid Base ◽

Acid Base Titration ◽

Titration Data

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A New Method for Plasminogen Standardization

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651297 ◽

1968 ◽

Vol 20 (03/04) ◽

pp. 548-554

Author(s):

J Gajewski ◽

G Markus

Keyword(s):

Proteolytic Activity ◽

Specific Activity ◽

Molar Ratio ◽

Sharp Transition ◽

Equivalence Point ◽

Constant Amount ◽

Residual Level ◽

Activity Measurements ◽

Complete Saturation ◽

Human Plasminogen

SummaryA method for the standardization of human plasminogen is proposed, based on the stoichiometric interaction between plasminogen and streptokinase, resulting in inhibition of proteolytic activity. Activation of a constant amount of plasminogen with increasing amounts of streptokinase yields linearly decreasing activities, as a function of streptokinase, with a sharp transition to a constant residual level. The point of transition corresponds to complete saturation of plasmin with streptokinase in a 1:1 molar ratio, and is therefore a measure of the amount of plasminogen present initially, in terms of streptokinase equivalents. The equivalence point is independent of the kind of protein substrate used, buffer, pH, length of digestion and, within limits, temperature. The method, therefore, is not subject to the variations commonly encountered in the usual determination based on specific activity measurements.

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The Effect of Stress and Warfarin on the Adrenal Gland in Relation to Spontaneous Hemorrhage, as Judged by Measurement of Adrenal Ascorbic Acid and Serum Corticosterone

Thrombosis and Haemostasis ◽

10.1055/s-0038-1653675 ◽

1971 ◽

Vol 26 (02) ◽

pp. 275-288 ◽

Cited By ~ 3

Author(s):

S Chattopadhyay ◽

D. D Johnson ◽

G. J Millar ◽

L. B Jaques

Keyword(s):

Ascorbic Acid ◽

Acid Concentration ◽

Ascorbic Acid Concentration ◽

Corticosterone Concentration ◽

Serum Corticosterone ◽

Spontaneous Hemorrhage ◽

Combined Action ◽

Series Of Experiments ◽

Pituitary Adrenal Axis

SummaryRats were subjected to the following procedures: No treatment, Stressor (10% NaCl i.p.), Warfarin for 7 days, Stressor followed by Warfarin; and groups were sacrificed at intervals for assessment of spontaneous hemorrhage and of adrenal ascorbic acid concentration. There was no hemorrhage in the no treatment and stressor groups; some hemorrhage in the warfarin group; profound hemorrhage with Warfarin + Stressor. The adrenal ascorbic acid concentration was found to be lower, 8 h and again 5 days after stress, and remained lower in the warfarin + stress animals. Warfarin had no effect on adrenal ascorbic acid level.In another series of experiments in which the stress consisted of an electric current to the cage floor for 6 sec over 15 min, rats were sacrificed daily for determination of serum corticosterone concentration and occurrence of spontaneous hemorrhage. There was a statistically significant increase of serum corticosterone concentration with stress, warfarin and combined warfarin and stress treatments (P< 0.001 for all three variables). There was a significant correlation (r = 0.96 and 0.89, P< 0.01) for serum corticosterone concentration with hemorrhage score and incidence of hemorrhage in stressed rats receiving warfarin, but not in those receiving only warfarin. The results indicate an activation, rather than an exhaustion, of the pituitary-adrenal axis during the combined action of anticoagulant and stress, which results in the development of spontaneous hemorrhage.

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