How to Prepared and Standardize of 0.1 N Iodine Volumetric Solution.

How to Prepared and Standardize of 0.1 N Iodine Volumetric Solution.

                                                             

Preparation of 0.1 Iodine Volumetric solution

➤ Glass ware and instruments required.

Beaker, Glass stirrer, Graduated Pipettes, Graduated cylinder, Analytical balance, Sucker, Volumetric flask, Burette, Conical Flask, Fume hood.

➤ Reagents required.

Iodine Reagent Grade,

Mol. wt. :- I,  126.90

Potassium Iodide Reagent Grade,

Hydrochloric Acid,

Arsenic Trioxide PS Previously dried for 1 hour at 105°,

Sodium Hydroxide 1 Normal solution,

Methyl Orange,

Sodium Biocarbonate,

Starch Solution.

➤ Preparation.

Transfer about 14 g iodine reagent grade in 1000 ml volumetric flask. Dissolve it in a mixture of 36 g potassium iodide reagent grade in 100 ml water, add 3 drops of hydrochloric acid and dilute it with water up to the mark.

➤ Standardization.

Accurately weigh about 0.15 g of arsenic trioxide PS, previously dried for 1 hour at 105°, in 250 ml conical flask. Dissolve it in 20 ml of 1 N sodium hydroxide solution by warming, if necessary. Dilute with 40 ml water and add 2 drops of methyl orange solution followed by addition of dilute hydrochloric acid until the yellow colour of the solution is changed to pink. Then add 2 g of sodium bicarbonate, dilute with 50 ml of water and add 3 ml of starch solution.

➤ Calculations.

                                         g  AS₂O₃  x  0.1 

N / M = ------------------------------------------------------------

                           0.004946  x   Burette reading  in ml