Equilibrium partial pressures and mean activity and osmotic coefficients of 0-100% nitric acid as a function of temperature

Abstract

Rational activity and osmotic coefficients and Henry's law constants K{sub Hx} (for the reaction HNO{sub 3(g)} = H{sup +}{sub (aq)} + NO{sub 3}{sup {minus}}{sub (aq)}), given as functions of temperature, enable p(H{sub 2}O) and p(HNO{sub 3}) to be calculated from {minus}60 to 120{degree}C, 0-100% HNO{sub 3}. Apparent molal enthalpies, heat capacities, and activity coefficients (derived from electromotive force (emf), freezing point, and partial pressure data) are represented with the use of the species-interaction models of Pitzer. Equations for the partial molal functions are given. The Henry's law constant is evaluated from p(HNO{sub 3}) data at 298.15 K, tabulated heats of formation, and heat capacities. Calculated p(H{sub 2}O) and p(HNO{sub 3}) over the entire concentration range agree with available data over 5 orders of magnitude of p(H{sub 2}O) and 7 orders of magnitude of p(HNO{sub 3}).