Oxidation of ascorbic acid by osmium(VIII)

1970 ◽  
Vol 48 (7) ◽  
pp. 1148-1150 ◽  
Author(s):  
U. S. Mehrotra ◽  
S. P. Mushran
Keyword(s):  
Ascorbic Acid ◽  
Ionic Strength ◽  
Hydrochloric Acid ◽  
Negligible Effect ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Kcal Mole ◽  
Hydrogen Ion Concentration ◽  
Influence Of Temperature ◽  
Entropy Of Activation

Reduction of osmium(VIII) by ascorbic acid has been studied in the presence of hydrochloric acid. The reaction is found to be directly proportional to the concentration of ascorbic acid and osmium(VIII) and to the reciprocal of the hydrogen ion concentration. In the proposed mechanism, the reacting species have been shown to be perperosmic acid and ascorbate ion; this was supported by the negligible effect of the ionic strength. Influence of temperature was studied in the range 25–40 °C, and the energy and entropy of activation were calculated as 14.1 ± 0.2 kcal mole−1 and −8.6 ± 0.1 e.u., respectively. Osmium(IV) was found to be a product of the reaction.

Mechanistic Information from the Effect of Pressure on the Kinetics of Hydrolysis of Iodopentaaquochromium(III) Ion

1975 ◽  
Vol 53 (24) ◽  
pp. 3697-3701 ◽  
Author(s):  
Milton Cornelius Weekes ◽  
Thomas Wilson Swaddle
Keyword(s):  
Ionic Strength ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Kinetics Of Hydrolysis ◽  
Rate Of Hydrolysis ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Aqueous Hclo ◽  
Conjugate Base

The rate of hydrolysis of iodopentaaquochromium(III) ion has been measured as a function of pressure (0.1 to 250 MPa) and hydrogen ion concentration (0.1 to 1.0 mol kg−1) at 298.2 K and ionic strength 1.0 mol kg−1 (aqueous HClO4–LiClO4). The volumes of activation for the acid independent and inversely acid dependent hydrolysis pathways are −5.4 ± 0.5 and −1.6 ± 0.3 cm3 mol−1 respectively, and are not detectably pressure-dependent. Consideration of these values, together with the molar volume change of −3.3 ± 0.3 cm3 mol−1 determined dilatometrically for the completed hydrolysis reaction, indicates that the mechanisms of the two pathways are associative interchange (Ia) and dissociative conjugate base (Dcb) respectively.

scholarly journals STIMULATION BY HYDROCHLORIC ACID IN THE CATFISH, SCHILBEODES

1931 ◽  
Vol 15 (2) ◽  
pp. 119-124 ◽  
Author(s):  
William H. Cole ◽  
James B. Allison
Keyword(s):  
Reaction Time ◽  
Hydrochloric Acid ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Acid Molecule ◽  
Experimental Conditions ◽  
Hydrogen Ion Concentration ◽  
Effective Stimulus ◽  
Wide Range ◽  
Increasing Function

1. The reaction of the catfish, Schilbeodes gyrinus Mitchill, to hydrochloric acid over a wide range of concentrations (from pH 1.82 to pH 6.83) has been studied under experimental conditions which reduced to a minimum all other stimuli. 2. As the [H+J increases within the limits mentioned, the reaction time of the fish decreases. In other words, the rate of the stimulation processes is an increasing function of the hydrogen ion concentration. 3. The effective stimulus is the hydrogen ion, since NaCl solutions of equivalent concentration were not stimulating. 4. Stimulation by hydrochloric acid is therefore correlated with the potential of the cation resulting from dissociation of the acid molecule.

INFLUENCE OF pH AND TEMPERATURE ON MYOSIN INACTIVATION

1961 ◽  
Vol 39 (2) ◽  
pp. 265-272 ◽  
Author(s):  
Gérard E. Pelletier ◽  
Ludovic Ouellet
Keyword(s):  
Structural Changes ◽  
Electrostatic Charge ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Kcal Mole ◽  
Order Process ◽  
Hydrogen Ion Concentration ◽  
First Order ◽  
Inactivation Process ◽  
Influence Of Ph

The inactivation of myosin adenosine triphosphatase activity was studied in 0.6 M potassium chloride solution at pH ranging from 7.0 to 10.8 and for 5 °C to 40 °C. The inactivation is a first-order process with respect to time and 0.6th order with respect to the concentration of protein. The rate of inactivation is independent of the pH for pH 7.0 to pH 8.5 at 35 °C and increases rapidly with pH at higher pH. At 12 °C, close to pH 10.4, the rate is inversely proportional to the 4.5th power of the hydrogen ion concentration. The energies of activation are 56 kcal mole−1 at pH 8.0 and 58 kcal mole−1 at pH 10.5. A discussion of the data stresses the importance of structural changes and indicates a possible role for the electrostatic charge in the inactivation process.

scholarly journals A STUDY OF THE ACTION OF ACID AND ALKALI ON GLUTEN

1919 ◽  
Vol 1 (4) ◽  
pp. 459-472 ◽  
Author(s):  
L. J. Henderson ◽  
Edwin J. Cohn ◽  
P. H. Cathcart ◽  
J. D. Wachman ◽  
W. O. Fenn
Keyword(s):  
Electrical Conductivity ◽  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Acid Base ◽  
Secondary Importance ◽  
Hydrogen Ion Concentration ◽  
Acid Base Equilibrium ◽  
Simple Chemical

In this paper there are reported studies of the acid-base equilibrium in systems containing gluten suspended in solution of hydrochloric acid and sodium hydroxide. The studies have involved measurements of the hydrogen ion concentration, of the electrical conductivity, and of the solution of the proteins. Further, measurements have been made of the swelling and of the viscosity of the gluten component of such systems. The results seem to show that simple chemical phenomena are most important in such systems, and that the modifications of these, resulting from colloidal and heterogeneous characteristics, are of secondary importance in determining the condition of equilibrium, though somewhat more significant in the progress of the system toward the condition of equilibrium.

Kinetics and mechanism of oxidation of allyl alchohol by chloramine-T in hydrochloric acid medium

1974 ◽  
Vol 27 (6) ◽  
pp. 1203 ◽  
Author(s):  
DS Mahadevappa ◽  
HMK Naidu
Keyword(s):  
Hydrochloric Acid ◽  
Allyl Alcohol ◽  
Hypochlorous Acid ◽  
Ion Concentration ◽  
Slow Step ◽  
Hydrogen Ion Concentration ◽  
Hydrochloric Acid Medium ◽  
Entropy Of Activation ◽  
Chloramine T ◽  
Kinetics Of

The kinetics of oxidation of allyl alcohol by chloramine-T in presence of hydrochloric acid (0.04-0.13M ) has been studied at O�C. The reaction shows first-order dependence on chloramine-T and hydrogen ion concentration and is independent of the concentration of alcohol. The energy and entropy of activation of the reaction have been found to be 12.3 kcal mol-1 and -33.2 e.u. respectively.Ionic strength has very little influence on the rate of reaction. A mechanism in terms of a fast interaction between allyl alcohol and hypochlorous acid formed by the hydrolysis of N-chloro-p-toluenesulphonamide in a slow step is proposed.

Reduction of chlorothallium(III) complexes by arsenic(III)

1973 ◽  
Vol 26 (10) ◽  
pp. 2115 ◽  
Author(s):  
PD Sharma ◽  
YK Gupta
Keyword(s):  
Ionic Strength ◽  
Acid Solution ◽  
Rate Constant ◽  
Perchloric Acid ◽  
Intermediate Formation ◽  
Chloride Ions ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Perchloric Acid Solution ◽  
Hydrogen Ion Concentration

The oxidation of arsenic(III) by thallium(III) in perchloric acid solution is inhibited by chloride ions. The reactivity of various chlorothallium(III) species is in the order Tl3+ > TlCl2+ > TlCl2+ > TlCl3 > TlCl4-. The rate decreases by increasing the hydrogen ion concentration and ionic strength. The redox process occurs by intermediate formation of a complex of thallium(III) and arsenic(III). The rate constant for the reaction between Tl3+ and arsenic(III) calculated from the data of the present investigation compared well with that of the reaction1 in the absence of chloride ions.

scholarly journals INFLUENCE OF TEMPERATURE AND HYDROGEN ION CONCENTRATION UPON THE SPORE CYCLE OF BACILLUS SUBTILIS

1919 ◽  
Vol 1 (4) ◽  
pp. 421-428 ◽  
Author(s):  
Arao Itano ◽  
James Neill
Keyword(s):  
Ph Value ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Practical Application ◽  
Vegetative Cells ◽  
Hydrogen Ion Concentration ◽  
Influence Of Temperature ◽  
Ph Values ◽  
Metabolic Products ◽  
Slight Growth

1. At 5°C. no germination took place. 2. At 25°C. and at 37°C. germination occurs if the hydrogen ion concentration of the broth is kept between pH 5 and pH 10, but not at higher or lower pH values. 3. The completion of the spore cycle likewise requires a hydrogen ion concentration between pH 5 and pH 10. 4. The spores can germinate when the pH value is 10, although after germination the vegetative cells multiply only to a very slight extent and soon pass into spores. 5. The slight growth and multiplication of vegetative cells in broth of pH 10 suggest that the formation of endospores in this medium must be caused largely by the unfavorable reaction of the medium rather than by the accumulation of metabolic products. 6. Automatic adjustment of the medium seems to play a rôle in the completion of the spore cycle. 7. The results are not only of theoretical importance but they have a practical application to the preservation of food by canning and by other methods.

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