Reproducibility of silver-silver halide electrodes

Abstract

Tests of the reproducibility in potential of the electrolytic, thermal-electrolytic, and thermal types of silver-silver chloride, silver-silver bromide, and silver-silver iodide electrodes, in both acid and neutral solutions, are reported. All of these silver-silver halide electrodes show an aging effect, such that freshly prepared electrodes behave as cathodes towards electrodes previously aged in the solution. They ar e not affected in potential by exposure to light, but the presence of oxygen disturbs the potentials of the silver-silver chloride and silver-silver bromide electrodes in acid solutions, and of the silver-silver iodide electrodes in both acid and neutral solutions. Except in the case of the silver-silver iodide electrodes, of which the thermal-electrolytic type seems more reliable than the electrolytic or the thermal type, the equilibrium potential is independent of the type, within about 0.02 mv. CONTENTS Page I. Introduetion_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 307 II. Apparatus and materials_ _ _ _ _ _ _ _ _ _ _ _ _ __ _ _ _ _ ___ _ _ ____ _ _ _ _ ___ _ _ _ _ 308 III. Silver-silver chloride electrodes__ _ _ _ _ _ _ _ __ _ _ _ _ _ _ __ _ _ __ _ _ _ _ _ _ __ _ _ _ 308 IV. Silver-silver bromide electrodes________ ______________________ __ __ 310 V. Silver-silver iodide electrodes_ _ _ _ _ __ _ _ _ _ _ _ _ _ __ _ _ _ _ _ __ _ __ _ _ __ _ _ _ _ 313