Ionic solvations in water + Co-solvent mixtures. Part 3.—Free energies of transfer of single ions from water into water + ethylene glycol mixtures

Abstract

The free energies of transfer for MX (where M = H⁺, Li⁺, Na⁺, K⁺ and X = Cl^–, Br^–, I^–, OH^–) from water into mixtures of ethylene glycol(E) and water, calculated from the available data on electrode potentials, have been separated into free energies of transfer for the individual ions, ΔG^°_t(M⁺) and ΔG^°_t(X^–), using values for ΔG^°_t(H⁺) calculated by the method involving the extrathermodynamic assumptions specified in Part 1. To calculate ΔG^°_t(H⁺), values for K_c=[EH⁺_solv]/[H⁺_aq][E_solv] have been determined using the spectrophotometric method with p-nitroaniline developed earlier. The values for ΔG^°_t(M⁺) and ΔG^°_t(X^–) obtained are compared with those already determined for mixtures of water with alcohols and with acetone.