The Determination of Gibbs Energy of the Exchange Reaction of Iodides Using Beta‐Alumina Solid Electrolytes

Abstract

EMF measurements of the cellnormalMo,normalNafalse(normals,normallfalse)|β″‐normalalumina|normalNaI+normalAg+normalAgI,normalMowere carried out in the temperature range of 309–647 K. The results were represented byE/V±0.00075=2.37566 )(±0.00620−3.1751 )(±0.1834×10−4×)(T/K )(309<T<369.6K E/V±0.00053=2.39487 )(±0.00672−3.6948 )(±0.1700×10−4×)(T/K )(369.6<T<422.4KandE/V±0.00044=2.46506 )(±0.00077−5.3566 )(±0.0145×10−4×)(T/K )(422.4<T<647KThe Gibbs energy of the exchange reactionnormalNa+normalAgI→normalAg+normalNaIwas determined from the EMF's. The standard Gibbs energy of formation of normalAgI in the reactionnormalAg)(normals+1/2 I2)(normalg=normalAgI)(normalswas obtained from the EMF's and normalΔGnormalNaI0 in literature asnormalΔGnormalAgI0/J·mol−1±50=−89930+52.64×)(T/K )(309<T<422.4KandnormalΔGnormalAgI0/J·mol−1±80=−82770+35.68×)(T/K )(422.4<T<647K

Thermodynamic Investigations of the NaI ‐ AgI System by the EMF Method Using Beta‐Alumina Solid Electrolyte

“…Experimental details have been described in our previous papers (1)(2)(3). Ag powder of 3N purity and AgI powder of 3N purity were mixed with a molar ratio of 1.000:4.000.…”

“…In our previous studies (1)(2)(3), the following cells were assembled, and EMF measurements were made Mo, Na(s, 1)lB"-aluminalAg + AgI + NaI, Mo [I] and Mo, Na(s, 1)lB"-aluminalAg + AgI + ~"-alumina, Mo [II] Cell [I]'s EMF's were accurately determined, and the values were used as a measure of the degree of ion exchange in the cathode of cell [II]. In order to investigate the ion exchange between Ag + ion in ~-AgI and Na + ion in B"-alumina powder, the Na content in the cathode was changed by shorting the electrodes through a resistor.…”

“…A complete valence of Na +, Ag +, and I-ions in the NaI and AgI was assumed, and the nonstoichiometry of Nal and Agl was ignored in Eq. [1] and [2]. As the solubilities of other components in the three phase are fairly small (2,3), each component can be regarded as a pure substance.…”

“…The NaI content in (Ag+_N~ § can be also changed by the "shortening electrodes method." When a given quantity of Na is transferred to the cathode of cell [III], the Na will react with AgI to form NaI (1,2). This reaction is represented by Eq.…”

Activity Measurements of Copper in Solid Copper-Nickel Alloys using Copper-Beta-Alumina

“…[1][2][3][4][5][6][7] Furthermore, application to thermodynamic studies or gas sensors by Na þ -0 -or 00 -alumina have also been made by many authors. [8][9][10][11][12][13][14][15][16][17][18][19][20] On the otherhand, in addition to ion-exchange research, there are some thermochemical researches involving the ionexchanged -or 00 -alumina. The following studies have been reported: measurements of Ag activity in solid Ag-Pd alloys using Ag þ -00 -alumina, 21) Ag activity in solid Ag-Au alloys 22) using Ag þ --alumina and Cu activity in liquid Cu-Sn alloys using Cu þ --alumina, 23) developments of SO x sensor using Ag þ --alumina 24,25) and NO x sensor using Ag þ --alumina, 26) determinations of 27) thermodynamic studies of sulfides using (Pb þ -Na þ )--alumina, 28) and so on.…”