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Química Nova

Print version ISSN 0100-4042

Abstract

LICHTIG, Jaim; ROCHA, Marcos; TABOAS, Regina G. Z.  and  ROPKE, Sacha. Permanganimetric titration of Fe3+ with the use of mettalic zinc as reducing agent - a contribution to undergraduate courses. Quím. Nova [online]. 1998, vol.21, n.5, pp. 659-661. ISSN 0100-4042.  http://dx.doi.org/10.1590/S0100-40421998000500021.

The classical volumetric titration of Fe2+ with MnO4-, used in some routine analysis as well as in undergraduate courses was improved. SnCl2 (to reduce Fe3+ to Fe2+) and HgCl2 (to oxidize excess SnCl2) were substituted by metallic zinc in boiling solutions, thus avoiding the toxic HgCl2 and Hg2Cl2; nitrate ions do not interfere in the improved methodology (it is an interference in the classical one) and the reproducibility of the determinations is increased by using metallic zinc. Determinations by students of undergraduate courses are discussed.

Keywords : permanganimetric titration; metallic zinc as reductor; undergraduate experiments.

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