IODATO-SILVER COMPLEXING EQUILIBRIA

摘要

Solubilities of silver iodate in aqueous solutions con¬taining various concentrations of lithium iodate have been measured for 25.0°C, 35.0°C. and 50.0°C. by means of an improved radioassay technique for silver activity. They have also been measured for the same temperatures in aqueous solutions containing various proportions of lithium iodate and lithium perchlorate. In the latter experiments, the ionic-strengths of all equilibrium solutions were fixed at a value of 1.00 M.nThe refined radiotracer method was based upon an electro-deposition procedure for mounting samples for counting. Samples of the equilibrium solution phases from the equili¬brated mixtures were carefully added to portions of strong nitric acid solutions which contained a predetermined amount of silver carrier (usually 10 mg.). To insure complete exchange between the tracers and the carriers, the solutions were evaporated to dryness. The residues were subsequently dissolved in ammoniacal cyanide plating baths and a current of 0.2 amp. was passed through the resulting solutions for a period of thirty-five minutes. The silver that was uniformly deposited was determined gravimetrically and was counted to determine its activity. From these data the activities corresponding to 100 per cent recovery of the carriers were computed. The applications of corrections for self-absorption and radioactive decay converted the observed activities to ones which were proportional to the tracer concentrations in the various aliquots of the equili¬brium solution phases. A knowledge of the specific activity of the silver used in the experiments made the radioassay complete.