. Estimation of Ferrous Ammonium Sulphate (FAS) Aim : To estimate the amount of ferrous ammonium sulphate (FAS) dissolved in ml of the given unknown solution volumetrically. For this you are given with a standard solution of ferrous sulphate ( FeSO )of normality . N and potassium permanganate solution as link solution.
Principle: Oxidation : + Fe Fe 5e → Reduction : + + 5Fe MnO 8H 5Fe Mn 4H O → Overall reaction : + + 5Fe MnO 8H 5Fe Mn 4H O → Short procedure: s.no Content Titration-I Titration-II Burette solution KMnO KMnO Pipette solution ml of standard FeSO ml of unknown FAS Acid to be added 20ml of 2N H SO (approx) 20ml of 2N H SO (approx) Temperature Lab temperature Lab temperature Indicator Self-indicator ( KMnO ) Self-indicator ( KMnO ) End point Appearance of permanent pale pink colour Appearance of permanent pale pink colour Equivalent weight of FAS = Procedure : Titration–I (Link KMnO )Vs ( Standard FeSO ) Burette is washed with water, rinsed with KMnO solution and filled with same FeSO solution up to the zero mark. Exactly ml of standard FeSO solution is pipetted out into the clean, washed conical flask. To this solution, approximately 20ml of 2N sulphuric acid is added. This mixture is titrated against KMnO Link solution from the burette.
KMnO is added drop wise till the appearance of permanent pale pink colour. Burette reading are noted, the same procedure is repeated to get concordant values. organic organic - - - - Titration –I (Link KMnO )Vs ( Standard FeSO ) s.no Volume of standard FeSO (ml) Burette readings Concordant value (Volume of KMnO ) (ml) Initial (ml) Final (ml) Calculation : Volume of KMnO (link) solution V ml Normality KMnO (link) solution N ?N Volume of standard FeSO solution V ml Normality of standard FeSO solution N . N According to normality equation: According to normality equation: