Oxidimetric Estimation with the Use of Standard Potassium Ferricyanide Solution

Abstract

The quantitative oxidimetric determination of Fe (II), Ti (III) and their mixture has been attempted by the use of ferricyanide having an oxidation potential as a standard solution, trisodium phosphate and sodium pyrrolecarboxylate as defilading agents. Fe (II) is found to be quantitatively oxidized in the case of using either trisodium phosphate or sodium pyrrolecarboxylate in the pH range 4.310.0. Quantitative oxidation of Ti (III) is possible by the use of trisodium phosphate at pH below 11.4 or sodium pyrrolecarboxylate at pH below 9.8. Cacotheline is found to be a suitable indicator for both iron and titanium. In the case of a mixture of iron and titanium, it is acidified with sulfuric acid to oxidize the titanium alone by the ferricyanide for its quantitative determination. Then the solution is treated with the above defilading agent to pH 4.310.0, and titrated with the standard solution of ferricyanide to find the sum of iron and titanium, from which the amount of titanium is subtracted to give the amount of iron.