Redox Titration with Potassium Permanganate - Lab Report Example

In the titration, ferrous ion (Fe2+) is oxidized to ferric ion (Fe3+) by the permanganate ion (MnO4-) and simultaneously the permanganate ion is reduced to manganese (Mn2+).
Method 9.8 grams of Ferrous Ammonium sulphate was carefully weighed and transferred to a volumetric flask. 150 millilitres of Sulphuric Acid was added to prevent hydrolysis and the mixture was stirred until the solid dissolved completely. The volume was made up to the mark with de-ionized water. 25 millilitres of the solution was removed from the flask with a pipette and titrated with the KMno4 solution until the first appearance of permanent pink colour. At the endpoint, all of the Fe2+ has been used up (reacted) and the purple permanganate is no longer converted to colourless Mn+2 so the pink colour remains and the reaction solution will have a permanent pink tinge to it (Web, Undated). A second titration was performed to substantiate data for analysis and reduce the scope for error.

The strength of the unknown Potassium permanganate solution in this reaction is calculated by titrating it a known molar solution of Ferrous Ammonium sulphate which provides us with the molarity of the KMnO4 solution. This experiment proves that when the molar composition of one chemical compound is known, and we can have a physical endpoint in a redox reaction with visible colour change, we can standardize the strength of an unknown compound by using the technique of volumetric titration.