Objective: To find out the molarity of the KMnO4 solution
Chemical principle: Potassium permanganate is a strong oxidizing agent. It dissolves in water to give intense purple solutions. It reacts with reducing agents and gives colourless Mn2+ ions. So the solution itself acts as the indicator for the titration, the end point is noted when the first permanent pink colour appears. The sulphuric acid is used as a catalyst for the reaction. The oxalic acid is heated before titration because if the temperature is too low, the interaction between the acid and the potassium permanganate will move too slowly.
250cm3 conical flasks X2 250.0cm3 volumetric flask 250cm3 beaker 100cm3 beaker
Burette White tile
Wash bottle Glass rod
Burette clamp and stand Pipette
Funnel Thermometer (10-110oC)
0.2M KMnO4 solution
Standard 0.1M iron (II) ammonium sulphate
Standard 0.05M oxalic acid dihydrate
2M of sulphuric acid
A. Standardization of KMnO4 solution with standard iron(II) salt solution 1. 25.0cm3 of the given KMnO4 solution was diluted to exactly 250cm3 in a volumetric flask. 2. 25.0cm3 of the standard iron (II) salt solution was added into a conical flask with the pipette. 3. 15cm3 of 2M sulphuric acid was added to the flask.
4. The solution was titrated with diluted KMnO4 solution until the first persistent pink colour obtained. 5. The titration was repeated to obtain 3 consistent results.
B. Standardization of KMnO4 solution with standard oxalic acid solution 1. 25.0cm3 of the standard 0.05M oxalic acid solution was added into a 250cm3 conical flask with the pipette. 2. 15cm3 of 2M sulphuric acid was added to the flask.
3. The mixture was heated to 70oc with the use of Bunsen burner. 4. The solution was titrated with...