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A NEW REDUCTIMETRIC REAGENT: IRON(II) IN A STRONG PHOSPHORIC ACID MEDIUM. TITRATION OF URANIUMVI WITH IRONII AT ROOM TEMPERATURE

Journal Article · · Talanta (England)
The formal redox potential of the Fe/sup III//Fe/sup II/ couple was determined in media of varying phosphoric acid concentration and found to decrease steeply with increasing phosphoric acid concentration. Above a certain concentration of phosphoric acid, the difference between the formal potentials of the U/sup VI//U/sup IV/ and Fe /sup III/Fe/sup II/ couples becomes s ufficientiy great to enable ironii to reduce uraniumvi even at room temperature. This is the reversal of the normal redox reaction--- oxidation of uranium/sup IV/ by iron/sup III/. A careful study of the various factors involved enabled the development of a new reductimetric titration of uraniumvi with iron/sup II/ in strong phosphoric acid medium (11.0 to 13.5M) at room temperature using either a potentiometric end point or a visual end point with methylene blue or thionine as an internal redox indicator. Because the new procedure enables the titration to be carried out at room temperature, it is more convenient than procedures involving titanium/sup III/ and chromium/sup II/ which require temperatures ranging from 60 to 90 deg C. The new procedure has a further advantage in that it can be used for the determination of uraniumvi even in the presence of iron/sup III/ and tungsten/sup IV/, using an electrometric end point. Also, the new procedure does not require the elaborate precautions which are necessary for the preparation and storage of titanium/sup III/ or chromium/sup II/ solutions. (auth)
Research Organization:
Andhra Univ., Waltair, India
NSA Number:
NSA-16-028893
OSTI ID:
4807132
Journal Information:
Talanta (England), Journal Name: Talanta (England) Vol. Vol: 9; ISSN TLNTA
Country of Publication:
Country unknown/Code not available
Language:
English