SOLUBILITY OF HOCL IN WATER AND AQUEOUS H2SO4 TO STRATOSPHERIC TEMPERATURES

Henry's law constants K'(H) (mol kg(-1) atm(-1)) for the reaction HOCl (g) = HOCl(aq) near room temperature, literature data for the associat ed enthalpy change, and solubilities of HOCl in aqueous H2SO4 (46 to 6 0 wt%) at temperatures relevant to the stratosphere (200K less than or equal to T less than or equal to 230K) are shown to be thermodynamica lly consistent. Effective Henry's law constants [H = mHOCl/pHOCl, in mol kg(-1) atm(-1)] of HOCl in aqueous H2SO4 are given by: In(H) = 6. 4946-mH(2)SO(4)(-0.04107 + 54.56/T)-5862(1/T-0-1/T) where T(K) is temp erature acid T-0 = 298.15K. The activity coefficient of HOCl in aqueou s H2SO4 has a simple Setchenow-type dependence upon H2SO4 molality.