Oxidations with alkaline permanganate using monovalent thallium for the back titration: Estimation of lead. selenium, tellurium and chromium

✍ Scribed by I.M. Issa; R.M. Issa

• Publisher: Elsevier Science
• Year: 1955
• Tongue: English
• Weight: 414 KB
• Volume: 13
• Category: Article
• ISSN: 0003-2670
• DOI: 10.1016/s0003-2670(00)87951-9

✦ Synopsis

Uttiuersily (Egypt)

SrAhrnll recommended the USC of formatc in the back titration of KMnO, in alkaline media. His method depends on the titration of KM&, in presence of Baf2 ions which check the reduction at the manganate state. The end-point is detected by the disappearencc of the pink colour through the green RaMnO, precipitate but the potentiometric estimation of the end-point was preferred to the visual metllod2*3. However, the reaction is not rapid especially near the end-point where it needs ~LIO minutes for the attainment of equilibrium.

Recently a new method for the macro-and microdetermination of thallium, by osidation with KMnO, in alkaline media, has been deviscd4. Reduction of KMnOo with Tl' was then tried and the reaction, which was performed under a variety of conditions, proved very suitable in back titrating excess permanganate in the course of several determinations. This reagent is preferred to formic acid on account of the shorter time taken to achicvc erluilibrium.