Standard potentials of silver, silver chloride electrode and protonation of tris (hydroxy methyl) amino methane in water-pyridine mixtures

The protonation behaviour of Tris(hydroxy methyl)amino methane was investigated in water-pyridine mixtures up to 30 wt% pyridine using the cell Pt, H2(g, 1 atm) Tris HCl(m1)Tris(w2)AgCl(5)Ag in solvent mixture at 30°C. The pKBH+of Tris H+decreases gradually with increasing composition of pyridine and this variation has been rationalised in terms of solute-solvent interactions in these mixtures through the relation ApK = pKBH+(s)— pKBH where the subscriptss and w represent the solvent mixture and water respectively and AGf°’s represent the Gibbs energies of transfer of the various species from water to water-pyridine mixtures. © 1992, Taylor & Francis Group, LLC. All rights reserved.