The acidic costants of 2-hydroxybenzohydroxamic acid in NaClO4 solutions at 25°C.

The protolysis equilibria of 2-hydroxybenzohydroxamic acid, H(2)SAX, have been studied at 25degreesC in different ionic media by potentiometric titration with a glass electrode. The media were 0.513, 1.05, 2.21 and 3.5 mol/kg NaClO4. The constants beta(-p)(H(2)SAXreversible arrowH(2-p)SAX(-p)+pH(+)), combined with salting effects of NaClO4 on H(2)SAX deduced from solubility determinations, were processed by the specific interaction theory, SIT, to give equilibrium constants at infinite dilution, log beta(-1)degrees = -7.655+/-0.013 and log beta(-2)degrees = -1 7.94+/-0.04, as well as specific interaction coefficients b(HSAX(-),Na+) = 0.12+/-0.01 and b(SAX(2-),Na+) = 0.17+/-0.02, molal(-1).