Potentiometric determinations of ionization constants of HSO4- and HCO3- ions in formamide

1977 ◽  
Vol 30 (12) ◽  
pp. 2621 ◽  
Author(s):  
UN Dash
Keyword(s):  
Ionization Constants ◽  
Thermodynamic Quantities ◽  
Different Temperatures

With the cell Ag-AgCl|KCl(m3), K2A(m2), KHA(m1), QH2-Q|Pt, where A stands for SO42- or CO32-, the ionization constants of the HSO4- and HCO3- ions in formamide have been determined at different temperatures. The standard thermodynamic quantities, ΔG�, ΔH� and ΔS�, have been calculated.

Thermodynamics of ionization of trans-crotonic and adipic acids in water; the silver – silver adipate electrode

1980 ◽  
Vol 58 (4) ◽  
pp. 323-327 ◽  
Author(s):  
Upendra Nath Dash ◽  
Uttam Kumar Nayak
Keyword(s):  
Adipic Acid ◽  
Silver Chloride ◽  
Ionization Constants ◽  
Thermodynamic Quantities ◽  
Liquid Junction ◽  
Different Temperatures ◽  
Heat Capacity Changes ◽  
Silver Silver ◽  
Silver Silver Chloride ◽  
Thermodynamics Of Ionization

The ionization constant, K, of trans-crotonic acid, and the first and second ionization constants, K1 and K2, of adipic acid have been determined in water at seven different temperatures ranging from 15 to 45 °C with the help of the cells without liquid junction using silver – silver chloride and quinhydrone electrodes. The variations of pK, pK1, and pK2 with temperature have been expressed by the equations[Formula: see text]and[Formula: see text]From the temperature coefficient of the ionization constants, the standard enthalpy, entropy, Gibbs energy, and heat capacity changes of the corresponding dissociation processes have been calculated. Using the values of ionization constants of adipic acid, the standard potential of the Ag(s)/Ag2Ad(s)/Ad2− electrode, and the related standard thermodynamic quantities for the electrode process[Formula: see text]have been calculated in water at those temperatures.

scholarly journals Studies on the application of the quinhydrone electrode in formamide. III. The ionization constants and related thermodynamic quantities of phthalic acid frome.m.f. measurements at different temperatures

1975 ◽  
Vol 28 (4) ◽  
pp. 793 ◽  
Author(s):  
UN Dash ◽  
B Nayak
Keyword(s):  
Phthalic Acid ◽  
Silver Chloride ◽  
Ionization Constants ◽  
Thermodynamic Quantities ◽  
Liquid Junction ◽  
Different Temperatures ◽  
Silver Silver ◽  
Silver Silver Chloride

The first and second ionization constants of phthalic acid have been determined, in formamide, at temperatures ranging from 5� to 45�C at 5� intervals, with the help of cells without liquid junction using quinhydrone and silver-silver chloride electrodes. By means of the Bjerrum equation, the distance r between the acidic groups has been estimated in formamide at different temperatures.

Studies on the application of the quinhydrone electrode in formamide. IV. The ionization constants and related thermodynamic quantities of picric acid from E.M.F. measurements at different temperatures

1975 ◽  
Vol 28 (4) ◽  
pp. 797 ◽  
Author(s):  
UN Dash ◽  
B Nayak
Keyword(s):  
Picric Acid ◽  
Ionization Constants ◽  
Thermodynamic Quantities ◽  
Temperature Range ◽  
Pka Value ◽  
Different Temperatures

The e.m.f, of the cell ���������������� Ag-AgCl/KCl(m3), KPic(m2), HPic(m1), QH2-Q|Au in formamide has been measured at 5� intervals over the temperature range 5-45�C. The pKa value of picric acid ranges from 2.19 � 0.12 at 5� to 1.16 � 0.08 at 45�.

scholarly journals Studies on the application of the quinhydrone electrode in formamide. VII. The ionization constants and related thermodynamic quantities of (E)-cinnamic acid from E.M F. measurements at different temperatures

1976 ◽  
Vol 29 (7) ◽  
pp. 1609 ◽  
Author(s):  
UN Dash
Keyword(s):  
Cinnamic Acid ◽  
Ionization Constants ◽  
Thermodynamic Quantities ◽  
Temperature Range ◽  
Pka Value ◽  
Different Temperatures

The e.m.f. of the cell Ag-AgCl/NaCl(m3), NaA(m2), HA(m1) QH2-Q/Pt (where HA is cinnamic acid) in formamide has been measured at 5� intervals over the temperature range 5-45�C. The pKa value of (E)-cinnamic acid ranges from 7.02 � 0.03 at 5� to 6.78 � 0.05 at 45�.

scholarly journals Mechanistic aspects of oxidation on L-tyrosine by diperiodatocuprate(III) complex in alkali media: a kinetic model

2009 ◽  
Vol 7 (4) ◽  
pp. 929-937 ◽  
Author(s):  
Nagaraj Shetti ◽  
Rajesh Hegde ◽  
Sharanappa. Nandibewoor
Keyword(s):  
Alkaline Medium ◽  
Activation Parameters ◽  
Spectral Studies ◽  
Slow Step ◽  
Isokinetic Temperature ◽  
Thermodynamic Quantities ◽  
Radical Intermediate ◽  
Different Temperatures ◽  
Reactive Oxidant ◽  
Reaction Constants

AbstractOxidation of an amino acid, L-tyrosine (L-Tyr) by diperiodatocuprate(III) (DPC) in alkaline medium at a constant ionic strength of 0.1 mol dm−3 was studied spectrophotometrically at different temperatures (288.1–313.1 K). The reaction between DPC and L-Tyr in alkaline medium exhibits 1:4 stoichiometry (L-Tyr:DPC). Intervention of free radicals was observed in the reaction. Based on the observed orders and experimental evidence, a mechanism involving monoperiodatocuprate(III) (MPC) as the reactive oxidant species has been proposed. A suitable mechanism is proposed through the formation of a complex and free radical intermediate. The products were identified by spot test and characterized by spectral studies. The reaction constants involved in the different steps of the mechanism were calculated. The activation parameters with respect to slow step of the mechanism were computed and are discussed. The thermodynamic quantities were determined for different equilibrium steps. Isokinetic temperature was also calculated and found to be 252.3 K.

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