Reaction of hydrogen with solutions of metals in liquid sodium

Abstract

The reaction rate of hydrogen with solutions of lithium (0–8.6), barium (0–6.1), strontium (0–4.0), and mercury (0–50 atom %) in liquid sodium is directly proportional to hydrogen pressure (0–35 kN m^–2) in the temperature range 390–565 K under conditions that solution composition and liquid-metal surface area remain effectively constant throughout reaction. Hydrogen reacts more rapidly with solutions containing respectively Li, Sr, and Ba than with pure Na; the reaction with Na–Hg solutions, however, is less rapid. The observed changes in the absolute rate constants, k_a, with solute metal concentration cannot be accounted for solely on the basis of measured activation-energy changes; the pre-exponential factor varies with both the solute metal and its concentration. The results are discussed with reference to possible changes in the energy profiles of conduction-band electrons in the liquid-sodium solutions.