Henry's law coefficient of hydrazoic acid

The Henry's law constant, K-H, of dilute aqueous hydrazoic acid, HN3, was determined experimentally for the first time as a function of concentration and temperature in a packed column. K-H, was found to be 12.0 +/- 0.7 M atm(-1) at 25 degrees C, mu = 0.02 M ((8.4 +/- 0.5) x 10(-3) kPa m(3)mol(-1)). The reaction enthalpy, Delta H, was found to be -31 +/- 1 kJ mol(-1). The results appear to be in good agreement with the only other published value for concentrated aqueous solutions at 30 degrees C.