Solubility of HBr in H2SO4/H2O and HNO3/H2SO4/H2O solutions

The solubility of HBr in H2SO4/H2O and HNO3/H2SO4/H2O solutions was determi ned by measuring the HBr vapor pressure over stirred bulk solutions using t unable diode laser spectrometry. The experimental results for the solubilit y of HBr in sulfuric acid solutions show good agreement with experimental l iterature data. However, there is a factor 2-6 discrepancy between experime ntal and model values. The solubility of HBr in sulfuric acid was parameter ized as a function of the H2SO4 concentration and temperature in the range 53-75 wt % H2SO4 and 195-250 K, respectively. The solubility of HBr in tern ary HNO3/H2SO4/H2O solutions was determined for the first time. An increase in the solubility was observed on exchanging H2SO4 by HNO3 at constant wat er weight fraction. This observation is in qualitative agreement with model calculations, however, the observed solubility change was much larger than predicted by the model calculations. The solubility of HBr in ternary solu tions was parameterized as a function of both the concentration of HNO3/H2S O4 and the temperature. The relations derived can be used for atmospheric m odeling of the influence of heterogeneous HBr reactions on atmospheric ozon e destruction.