Journal of Solution Chemistry

, Volume 9, Issue 2, pp 109-128

First online:

Ionization of aqueous toluic acids: Conductance and thermodynamics

  • Laurence E. StrongAffiliated withChemistry Department, Earlham College
  • , Thomas G. CopelandAffiliated withChemistry Department, Earlham College
  • , Margaret DarraghAffiliated withChemistry Department, Earlham College
  • , Carter Van WaesAffiliated withChemistry Department, Earlham College

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Conductivities of aqueous solutions ofortho-, meta-, andpara-toluic acids have been measured for the concentration range 0.1–2 millimolar and at 5° intervals from 5 to 100°C. At each temperature pK a(m) andA 0 have been calculated using the paired ion model recently described by Fuoss. Thermodynamic parameters have been calculated for the ionization of each acid, and Walden products for the anions. Results are discussed in terms of contributions to acidity by enthalpy and entropy changes as well as by hydration of the various solute species.

Key words

Acid ortho-toluic meta-toluic para-toluic equilibrium constant ionization heat capacity enthalpy entropy conductivity aqueous solution Walden product