Ex.No: 03. ESTIMATION OXALIC ACID
AIM:
To estimate the amount of Oxalic Acid dissolved in 500ml of the given solution volumetrically. For this you are given with a standard solution of ferrous ammonium sulphate (FAS) of normality 0.1N and Potassium Permanganate as link solution.
PRINCIPLE:
During these titration, Oxalic acid is oxidized to CO2 and MnO4- ions (from KMnO4) is reduced to Mn2+ ion.

*Since one mole of Oxalic acid releases 2 moles of electrons, the equivalent weight of oxalic acid is = 106/2= 63(oxalic acid is dihydrated)
PROCEDURE:
TITRATION – I: (Standard FAS) Vs (Link KMnO4):
Burette is washed with water, rinsed with KMnO4 solution and filled with the same KMnO4 solution up to zero mark. Exactly 20ml of std FAS solution is pipetted out into the clean, washed conical flask. To this FAS solution, approximately 20ml of 2N H2SO4 is added. This mixture is titrated against KMnO4 link solution from the burette. KMnO4 is added drop wise till the Appearance of permanent pale pink colour. The burette reading is noted and the same procedure
is repeated to get concordant values.
TITRATION – II: (Link KMnO4) Vs (Unknown FeSO4)
Burette is washed with water, rinsed with KMnO4 solution and filled with the same KMnO4 solution up to zero mark. Exactly 20ml of unknown Oxalic acid solution is pipetted out into the clean, washed conical flask. To this Oxalic acid solution, approximately 20ml of 2N H2SO4 is added. This mixture is heated to 60°C - 70°C using Bunsen burner and that hot solution is titrated against KMnO4 link solution from the burette. KMnO4 is added drop wise till the Appearance of permanent pale pink colour. Burette readings are noted and the same procedure is repeated to get concordant values.