Thermoelectric powers and entropies of the hydrogen ion

Abstract

Initial and final (steady-state) thermoelectric powers have been determined for the strong acids HCl, H2S04, HClO4 and HNO3 at a series of concentrations by the use of quinhydrone electrodes at a mean temperature of 25°C. From these values have been determined entropies of transport and transported entropies as well as their concentration dependence. By extrapolation the standard transported entropy of the hydrogen ion has been determined as 5-1 cal/mole deg. Support for the results has been found in other data.

The standard entropy of transport of potassium chloride in the water–methanol system at 298 K

“…According to the basic rules of irreversible processes thermodynamics,14 the initial and steady-state TEP of cell (1) [reaction (1)] are determined by the equations :…”

The Transport Entropy of Hydrogen Ion in the Water-Ethanol System

“…In the present study, however, we have found that electrode systems are quite stable and even for the ethanol concentration as high as 99.9% by weight, the eo value may be reproduced within _+ 7 ~V/deg and the E~ value to within ___ 5 ~V/deg. It is also interesting to note that no such difficulty was observed by Breck, Cadenhead, and Hammerli (6), where they have carried their thermocell measurements in aqueous solvent up to as high as 1.0N in HC1. The results of e~ measurements are shown in Table I.…”

“…Cell solutions were prepared by the method described by previous authors (6,8). The quinhydrone (Fisher reagent grade) was washed several times with the acid solution prior to its addition into the cell solution.…”

“…The initial thermoelectric powers, co(X), were measured by the "static method" using the N-shaped cell (8) with platinum electrodes. Cell solutions were prepared by the method described by previous authors (6,8). The quinhydrone (Fisher reagent grade) was washed several times with the acid solution prior to its addition into the cell solution.…”

“…F ~H = -~ SH2 --Se --S~+ + tcl-S*HcI [6] Since SH2 (1 atm) and Se are available, S*HCl and SH+ may be readily obtained. The corresponding molar heats of transfer, Q*HCl may then be calculated by the formula Q*HCl = TS*HcI.…”