Preparation and standardization of 0.1 M Potassium Iodate volumetric solution

1.0          Scope:

1.1                   The procedure is applicable to preparation and standardization of 0.1 M Potassium Iodate volumetric solution.

2.0          Apparatus:

2.1        Analytical balance.

2.2        50 ml burette (0.1 ml graduated).

2.3        250 ml stoppered conical flasks.

2.4        1000 ml volumetric flask.

2.5        200 ml volumetric flask.

2.6        100 ml volumetric flask.

2.7        25 ml pipette.

2.8        20 ml pipette.

2.9        10 ml pipette.

2.10      1 ml pipette.

2.11      50 ml beaker.

       (Use Class 'A' glassware)

3.0          Reagents:

3.1        Potassium iodate (Analytical grade).

3.2        Potassium iodide (Analytical grade).

3.3        Sulphuric acid.

3.4        0.1 M Sodium thiosulfate volumetric solution

3.5        Starch Soluble

3.6        Water.

4.0                Procedure:

4.1                    Preparation of starch solution:

4.1.1           Triturate 1.0 g of starch soluble with 5.0 ml of water and add, stirring continuously, to 100 ml of boiling water containing 10 mg of mercuric iodide.

4.2              Preparation of 0.1 M Potassium Iodate:

4.2.1            Weigh accurately about 21.4 g Potassium iodate, previously dried at 110°C to constant         weight, in sufficient water to produce 1000 ml.

4.3  Standardization:                                                 Normality Limit : ±10% (0.09 to 0.11 )

4.3.1            Dilute 25.0 ml of 0.1 M Potassium Iodate solution to 200 ml with water. To 20.0 mL of this solution, add 2 g of potassium iodide and 10ml of 1M Sulphuric acid. Titrate with 0.1 M sodium thiosulfate VS using 1 ml of starch solution as indicator and continue titrating until the solution is colorless to the blue starch - iodine complex.  

1 ml of 0.1 M sodium thiosulphate is equivalent to 0.003566 g of KIO3.

                    Calculation:

Molarity of 0.1 M Potassium Iodate:

                           Titer vol. of 0.1 M sodium thiosulphate x Molarity of 0.1 M sodium thiosulphate x 0.003566 x 1000 x 200

                =   ----------------------------------------------------------------------------------------------------------------------------------------

                                           Wt. of Potassium iodate x 25 x 20

Standardization should be carried out in triplicate.

Report the triplicate mean value.

The % RSD of triplicate mean value should not be more than 2.0.

5.0               Storage:

5.1               Store in amber-coloured, glass stoppered bottles.

6.0               Shelf Life:

6.1  Shelf life of the above solution shall be one month from the date of preparation.

6.2  Restandardize the above solution once in 15 days.

Note: Discard the volumetric solution whenever sedimentation, crystallization or fiber particles observed in the reagent bottle.

                                                            

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