PREPARING 0.1N IODINE SOLUTION

 0.1N IODINE SOLUTION

a) WEIGH 12.7 GM OF IODINE SAMPLE AND 21 GM OF POTASSIUM IODIDE AND MIX THEM PROPERLY (ANY SMALL PARTICAL SHOULD NOT BE REMAIN). THEN MAKE IT UPTO 1000 Ml BY USING DISTILLED WATER.

b) STADARISATION WITH 0.1N SODIUM THIOSULPHATE (Na₂S₂O₃.5H₂O, Eq. Wt. 248.19)

TAKE 25ML OF ABOVE PREPARED IODINE SOLUTION AND TITRATE IT AGAINST 0.1N SODIUM THIOSULPHATE SOLUTION UNTILL THE SOLUTION HAS PALE YELLLOW COLOUR THEN ADD APPROX 2Ml. OF 2% STARCH SOLUTION AS AN INDICATOR AND CONTINUE THE TITRATION. END POINT IS BLUE TO COLOURLESS.

CALCULATION

    B.R.   x  NORMALITY OF SODIUM THIOSULPHATE