Fe_Analysis_by_Redox_Titration

Fe_Analysis_by_Redox_Titration - Fe Analysis by REDOX...

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Fe Analysis by REDOX Titration Reaction of Ferrous Ion with Permanganate Potassium permanganate is a widely used as an oxidizing agent in volumetric analysis. In acid solution MnO 4 - undergoes reduction to Mn +2 . Since the permanganate ion, MnO 4 - , is pink and the Mn +2 ion is colorless, the endpoint using permanganate as the titrant can be taken as the first permanent pink color that appears in the titration. In this experiment KMnO 4 will be used to determine the percentage of Fe +2 by mass in an unknown sample. The oxidation of Fe +2 to Fe +3 is carried out acidic solution to prevent the air oxidation of Fe +2 . Phosphoric acid, H 3 PO 4 , is added to form a colorless complex with Fe +3 ion. The KMnO 4 solution (about 0.02M) is first standardized by titration using Mohr’s salt, ferrous ammonium sulfate hexahydrate, (Fe(NH 4 ) 2 (SO 4 ) 2 (H 2 O) 6 as the source of Fe 2+ . The Fe +2 is oxidized to Fe +3 while the MnO 4 - is reduced to Mn +2 . The exact molarity of the KMnO 4 is then determined. Fe(NH 4 ) 2 (SO 4 ) 2 (H 2 O) 6 Fe 2+ (aq) + 2NH 4 + (aq) + 2SO 4 2- (aq) +8H 2 O(l) MnO 4 - + Fe +2 Mn +2 + Fe +3 (unbalanced) Next the standardized KMnO
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Fe_Analysis_by_Redox_Titration - Fe Analysis by REDOX...

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