Question

Calculate the Iodine value of corn oil using the following information: N of sodium thiosulfate: 0.1 N mL of sodium thiosulfate needed to titrate the blank: 48 mL mL of sodium thiosulfate needed to titrate the blank: 39 mL Weight of corn oil sample: 0.1 g

Answer 1

From the from two volumes of sodium thiosulfate, one should be of blank and other one for the test.

The Iodine number is defined as the number of grams of iodine which will add to 100 grams of fat or oil. Iodine value shows the degree of unsaturation of the constituent fatty acids in an oil or fat and is thus a relative measure of the unsaturated bonds present in the oil or fat. Iodine value is expressed in grams of iodine absorbed by 100 gms of oil or fat.

Volume of sodium thiosulfate used= [Blank-Test] ml=48-39=9ml

Iodine No. of fat= (Equivalemt wt. of Iodine*Vol of Na₂S₂0₃ used*Normality of Na₂S₂0₃ * 100* 10^-3)/Weight of fat sample used for analysis(g)

=127*9*0.1*100*10^-3/0.1

=114.3