Abstract
In the colorimetry of tungsten, coloration with the Wellknown stannous chloride, potassium thiocyanate, hydrochloric and sulfuric acids was comparatively examined in detail using photoelectric colorimeter. It was thereby confirmed that a rapid and accurate results can be obtained by following the conditions listed below, and some considerations were made: A sample solution containing up to 3 mg./100 ml. should be kept below 20 ml., to which are aded 5-10 ml. of sulfuric acid, approx. 20 ml. of hydrochloric acid, and 5 ml. of 2M stannous chloride. This mixture is cooled to below 25°, is diluted to 100 ml. with 10 ml. of 20% potassium thiothianate and 30 ml. water, and measured at once.
