Question

If a 0.2g of oil consumed 1ml of sodium thiosulphate, calculate its iodine value and classify the oil?

Answer 1

Iodine value is a measure of the degree of unsaturation in fats and oils. It is essentially the number of grams of iodine consumed by 100 g of fat. If the iodine number is in the range of 0-70 then it is a fat, any value above 70 is considered an oil.

Formula:

Iodine number = (ml of 0.1 N Thiosulphate blank- ml of 0.1N thiosulphate test) * 12.7 *100/1000* wt of sample

vol of thiosulphate required to titrate test sample (given oil) = 1 ml

wt of sample = 0.2 g

Information on the volume of thiosulphate required to titrate the blank solution is essential for calculation.

Iodine number = (X-1.0) * 12.7 * 100/1000* 0.2 = (X-1.0)*6.35