Rabindra N. Roy

University of California, Berkeley, Berkeley, California, United States

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Publications (3)4.85 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The electrochemical cell without liquid junction: , , KCl(m2), CO2(m3)/AgCl/Ag has been used to determine the first ionization constant of carbonic acid and the activity coefficient of KHCO3 in potassium chloride solutions and in water at 278.15, 298.15, and 318.15 K. The molality ratios were approximately 1, 2, 3, 4, and 6. The range of molality for KHCO3 varied from 0.015 to about 1 mol·kg−1, whereas that for KCl ranged from 0.01 to about 0.34 mol·kg−1. The average value of pK1 for all different ratios of at 298.15 K is 6.360, which is the same as the previous result of 6.360 for NaHCO3 + NaCl + H2O. The results were also treated by fitting to the Pitzer equations for mixed electrolytes. All parameters reliably and accurately known from other systems were adopted leaving only the KHCO3 parameters to be determined. From these results, values are calculated for activity and osmotic coefficients of pure KHCO3 at selected molalities and temperatures as well as the trace activity coefficient of KHCO3 in KCl.
    The Journal of Chemical Thermodynamics 01/1983; 15(1):37-47. · 2.42 Impact Factor
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    ABSTRACT: The second-step thermodynamic dissociation constants of the zwitterionic form of bes, a useful secondary-standard biological buffer, have been determined at 278.15 to 328.15 K in 10, 30, and 50 mass per cent of tetrahydrofuran (thf) + water solvent mixtures. E.m.f. measurements of (hydrogen + silver bromide) cells without liquid junction have been made at intervals of 5 K for the process bes±(S) = bes−(S) + H+(S). The values of pK2 are given as a function of T by the equation: for 10 mass per cent: for 30 mass per cent; and for 50 mass per cent of thf. The results are compared in terms of standard Gibbs free energies, enthalpies, and entropies of transfer, from water to 50 mass per cent methanol + water, 2-methylpropan-2-ol + water, and thf + water.
    The Journal of Chemical Thermodynamics 11/1982; 14(11):1011-1018. · 2.42 Impact Factor
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    ABSTRACT: The standard potential of (silver + silver chloride) and (silver + silver bromide) electrodes have been determined from electromotive-force measurements on cells of the type: where XCl or Br. The e.m.f. measurements in this mixed solvent (dielectric constant = 47.85 at 298.15 K) were performed at 11 temperatures from 278.15 to 328.15 K, and were used to derive (a) the mean molality-based activity coefficients of HCl and HBr; (b) the relative partial molar enthalpies of HCl and HBr at 298.15 K; and (c) the standard thermodynamic quantities for the transfer of HCl and of HBr from the standard state in water to the standard state in (water + 50 mass per cent of diglyme). The molality of HCl and HBr covered the range from 0.0098 to 0.1 mol kg−1. The standard e.m.f. was determined by an extrapolation method making use of the extended terms of the Debye-Hückel theory. The information obtained sheds some light on the nature of ion-ion and ion-solvent interactions of HCl and HBr in this (water + dipolar aprotic solvent) mixture.
    Journal of Chemical Thermodynamics - J CHEM THERMODYN. 01/1981; 13(6):537-548.

Publication Stats

14 Citations
4.85 Total Impact Points

Institutions

  • 1983
    • University of California, Berkeley
      Berkeley, California, United States
  • 1981–1982
    • Springfield College
      Springfield, Minnesota, United States