Pressure and Temperature Effects on the Excess Conductance of the Hydroxide Ion in Water

Abstract

Abstract The limiting molar conductances, Λ°, of sodium hydroxide were determined at 15, 25, and 40 °C as a function of the pressure up to 1500 kgf cm−2 (1 kgf cm−2=0.9807×105 Pa) from the conductances measured in a dilute concentration range (1×10−3–2×10−2M, 1 M=1 mol dm−3). The excess conductances at an infinite dilution, λ°E, of the hydroxide ion, as estimated by [λ°E(OH−)=Λ°(NaOH)−Λ°(NaCl)], were found to increase with an increase in the pressure and temperature, as well as those of the oxonium ion, λ°E(H3O+). However, there was a significant difference in the magnitude of λ°E, itself, and a slight difference in the magnitude of the pressure and temperature dependences of λ°E between hydroxide and oxonium ions. These results may be related to a difference between the proton-jump mechanisms of the hydroxide and oxonium ions.