Reply to Comment on “Thermodynamic Models for the (HClO4 + NaClO4){aq} and (HBr + NaBr){aq} Systems at 298.15 K and 0.1 MPa” authored by Oakes, C. S., Ward, A. L., and Chugunov, N. Journal of Chemical & Engineering Data 2023, 68, 2554–2562

In their comment on the article by Oakes et al. ( J. Chem. Eng. Data 2023, 68, 2554−2562 ), Xiong and Wang (DOI: 10.1021/acs.jced.4c00056) suggest that our model parameters are invalid and defend their parametrization methodology. Their methodology defense rests on the assertion that the Pitzer model is empirical and that their parameters were fit to “qualified” data and tested against independent data. Their claim of invalidity rests upon the supposition that our model produces alkaline pHs for NaClO4{aq} and NaBr­{aq}. They also imply that isopiestic data, used in part to derive our model parameters, cannot be used to derive trace activity coefficients. We refute the claims that our model produces incorrect values of pH and pHm, that trace activity coefficients cannot be derived from isopiestic measurements, and that statistically and physically meaningful Pitzer model parameters involving trace solutes can be fitted to solubility measurements.