Thorium Nitrate Colorimetric Method

Viscosity of Dimethylpolysiloxane. .. 848 Method I Thorium Nitrate Colorimetric ... 

Elemental composition (in anhydrous salt) Th 48.33%, N 11.67%, O 40.00%. The aqueous solution may be analyzed for thorium (See Thorium) and for nitrate ion by ion chromatography, nitrate ion-specific electrode, and colorimetric methods. The water of crystaUization can be determined by DTA, TGA, and other gravimetric methods. 

Higashi measured the solubility of thorium hydroxide at room temperature from the direction of oversaturation. Thorium nitrate solutions (3 x 10 M, pH 2.5) were titrated with 0.1 M NaOH to pH values in the range 4-8. After precipitation of Th(OH)4(s), the Th concentration and pH were measured after 30 minutes, 12 hours, 1, 2, 3, 7, 15, 30 and 100 days. No ionic medium was used in the experiments and the pH was measured using a glass electrode, but with no information about calibration procedures. Thorium concentrations were measured by a colorimetric method after filtration through filter... 

Application of the oxygen-flask combustion method to the determination of fluorine in organic combination has now been made by a number of workers. The fluoride in solution after combustion may be determined by thorium nitrate titration or colorimetrically as the alizarin complexan chelate or with a chloranilate (see Halogen Acids and Salts, p. 302). A method based upon the alizarin complexan chelate is given in Appendix IV. 

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