(P3E.8* Nitric acid hydrates have received much attention as possible catalysts for heterogeneous reactions that bring...
(P3E.8* Nitric acid hydrates have received much attention as possible catalysts for heterogeneous reactions that bring about the Antarctic ozone hole. Worsnop et al. (Science 259, 71 (1993)) investigated the thermodynamic stability of these hydrates under conditions typical of the polar winter stratosphere. They report thermodynamic data for the sublimation of mono-, di-, and trihydrates to nitric acid and water vapours, HNO3.nH2O(s) → HNO3(g) + nH2O(g), for n= 1, 2, and 3. Given 4_Gº and AHⓇ for these reactions at 220 K, use the Gibbs-Helmholtz equation to compute 4_G® for each at 190 K. n 4_GⓇ/(kJ mol-') 4H®/(k) mol-) 1 46.2 127 2 69.4 188 3 93.2 237