The solvent deuterium isotope effect on the dissociation constant of iodic acid

Abstract

The solubilities of hydrated and deuterated copper(II) iodate in HClO₄–H₂O and DClO₄–D₂O solutions respectively, were measured at 1, 15, 25 and 35°C, the perchloric acid concentrations ranging from 0 to 1.0 m. These experimental results were used to calculate the solvent deuterium isotope effect, ΔpK, on the dissociation constants of HIO₃ and DIO₃. At ionic strength I = 1.0 m (Li) ClO₄ the following values were obtained, ΔpK = pK (D₂O) - pK (H₂O): 0.359 ± 0.027 (1°), 0.323 ± 0.015 (15°), 0.323 ± 0.047 (25°), 0.380 ± 0.025 (35°).