Abstract
The method for the estimation of chlorides in chromium plating bath by using chloride-electrode was studied and the following results were obtained. The potential was greatly controlled by the concentration of chromic acid in the determination of the chlorides in chromic acid by using chlorideelectrode. Therefore, it was impossible to estimate the chlorides in chromic acid directly by using chloride-electrode. However, the potential was not controlled by the concentration of chromic acid in the chromium plating bath, to 10ml of which had been added 5g of sodium acetate; therefore, it was known that the chlorides in the bath could be estimated by using chloride-electrode. In such a process, the quantity of sample solution increased by the addition of sodium acetate and the concentration of chlorides should be lower than that of the original plating bath. Whereas, the ionic strength of the sample solution increased by the addition of sodium acetate, and it offset the increase of activity of chlorides, by which the chloride concentration of the sample solution was determined as the same value as that of the original plating bath.
