How do you Prepare 0.02 M Potassium Permanganate?

Preparation of 0.02 M Potassium Permanganate

Dissolve 3.2 gm of potassium permanganate in 1000 ml water, heat on the water bath, allow stand for 2 days and filter through glass wool. 

How do you Make 0.1M. and 0.001M Sodium Thiosulphate

Standardization of 0.02 M Potassium Permanganate

To 25 ml of this solution in a glass stoppered flask add 2 gm of potassium iodide, followed by 10 ml of 1M sulphuric acid. Titrate the liberated iodine with 0.1 M sodium thiosulphate using 3 ml of starch solution, added towards the end of the titration, as the indicator. Perform the blank determination and any necessary corrections.

Each 1 ml of 0.1M sodium thiosulphate is equivalent to 0.00316 gm of KMnO₄.

 Calculation

                                  M2 x V2
           Molarity  =  ----------------------
                                       V1                                       

                        Where             M2  = molarity of 0.1M sodium thiosulphate solution.    

                                                V2  = volume of 0.1 M sodium thiosulphate consumed in

                                                            ml    

                                                V1  = volume of 0.1 M potassium permanganate taken in ml.

ACCEPTANCE CRITERIA

1) The accuracy of the solution should be within ± 10% of the theoretical concentration.

2) RSD* of the triplicate results of standardization / re-standardization should not be more  

            than 0.2 %.