Rate of reaction of hydrogen with liquid lithium: comparison with sodium and potassium

Abstract

Rates of reaction of hydrogen with a clean liquid-lithium surface have been determined at 217, 244, 257, 270, and 295 °C at pressures up to 23.7 kN m^–2. The rates range from 4.683 × 10⁶ to 27.919 × 10⁶ mm s^–1(kN m^–2)^–1 at 217 and 295 °C respectively. The reaction is first order with an activation energy of 52.8 kJ mol^–1 which is lower than that for potassium (66.5 U mol^–1) and sodium (72.4 kJ mol^–1). Liquid lithium reacts more rapidly than do these metals; the rates at 250 °C for Li, K, and Na are in the nearest whole number ratio of 43 : 4 : 1. The results are consistent with a report that small additions of lithium to sodium enhance the rate of hydrogen absorption.