Dissolve 25 gm of sodium thiosulphate and 200 mg of sodium carbonate in carbon dioxide-free water to produce 1000 ml. Standardize the solution in the following manner  Â
{tocify} $title={Table of Contents}Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â
STANDARDISATION (TRIPLICATE)
Weigh accurately about 0.2 gm. of potassium bromate and dissolve sufficient water to produce 250 ml. To 50 ml. of this solution add 2 gm. of Potassium Iodide and 3 ml. of 2M Hydrochloric acid and titrate with 0.1M sodium thiosulphate solution using starch solution added towards the end of the titration, as an indicator until the blue colour is discharged to end-point Â
Every 1 ml of 0.1M sodium thiosulphate is equivalent to 0.002784gm of KBrO3
Calculation
                    Wt. of potassium bromate(mg) × 50 x Potency of potassium bromate× 0.1
 Molarity =  ------------------------------------
                      Volume consumed (ml) x 2.784 x 250 × 100
SODIUM THIOSULPHATE (0.001M)
PREPARATION
Take 10 ml 0.1M of sodium thiosulphate in a 1000 ml volumetric flask and produce 1000 ml with carbon dioxide-free water. Standardize the solution in the following manner     Â
STANDARDISATION (TRIPLICATE)
Weigh accurately about 0.05 gm. of potassium bromate and dissolve sufficient water to produce 500 ml. To 10 ml. of this solution add 2 gm of Potassium Iodide and 3 ml. of 2M hydrochloric acid and titrate with 0.001M sodium thiosulphate solution using starch solution added towards the end of the titration, as an indicator until the blue colour is discharged to a blue coloured end-point Â
Each 1 ml of 0.001M sodium thiosulphate is equivalent to 0.00002784gm of KBrO3.
Calculation
               Wt. of potassium bromate(mg) x 10 x Potency of potassium bromate ×0.001Â
 Molarity = -----------------------------------                     Â
       Volume consumed (ml) x 0.02784 x 500 × 10
Preparation and Standardization of 0.1M, and 0.05M Perchloric Acid