Glass Electrodes for the Direct Measurement of Sodium Ion Activity

Abstract

One Lithia Alumina Silicate glass and three Lithia Soda Alumina Silicate glasses were melted and studied for their suitability as sodium electrodes. Out of these only No. 1 glass responded to the activity of Na⁺ ions and produced slope values very near to the ideal Nernst value at the temperature when the measured e.m.f data of these electrodes were plotted against the corresponding pNa (—Log a_Na⁺) values of the pure NaCl solutions. Also, the electrodes from No. 1 glasses were found to have hardly any sensitivity towrds K⁺ ions when their e.m.f. was measured in pure KCl solutions. The interfering effect of K⁺ ions on the activity measurements of Na⁺ ions was also examined and found to be insignificant.