To Determine the iodine value of oil. there are mention in theory and practical

1. B-Pharmacy 2nd Year 3rd Semester
Pharmaceutical Organic Chemistry II
Topic: To determine Iodine value
Miss. Puja R. Basule
M-Pharm
Pharmaceutical Chemistry

2. Ex.no.4: Determine the iodine value of oil
• Iodine Value:
 Is define as the number of Gram of iodine absorbed by 100gm of fat.
 Is the number of gram of iodine that would add to C=C present in 100gm
of fat or oil.
• Apparatus: Beaker, conical flask, pipette, burette, burette stand, iodine
flask, glass pipette, measuring cylinder, Reagent bottle etc.
• Chemicals: Iodine mono chloride Reagent, potassium Iodine,
Standardized 0.1N Sodium thiosulphate 1% Starch indicator solution,
Chloroform.

3. • Theory:
Iodometric titration
No of iodine consumed
no of C=C
Methods: 1. Iodine
Monochloride method or
Wijs method
2. Iodine monobromide
method or Hanus Method
3. Pyridine Bromide
Method

4. Procedure:
 Standardization of Sodium Thiosulphate Solution
• Weight accurately 5g of Potassium dichromate which has been previously
dried at 1050C±20C for 1hr.
• Dissolved it in distilled water make up to 1 L.
• Pipette 25ml of sodium thiosulphate solution in 250ml conical flask.
• Add 5ml of concentration HCL
• Add 15ml of a 10% potassium iodide solution.
• Allow stand for 5min and then titrate the content with sodium thiosulphate
solution using starch as indicator at the end.
• End point is change of blue colour to green

5.  Wijs Method:
 Weight accurately 10ml sample (oil/fat) in iodine flask.
 Add 25ml of carbon tetrachloride mix it.
 Pipette 25ml of Wij’s solution and replace the glass stopper after wetting
with potassium iodine solution.
 Keep the flasks in dark place for half an hour for non drying and
semidrying oils and 1hr for drying oils.
 After standing, add 15ml of potassium iodide solution, 100ml of recently
boiled and cooled water, rinsing in the stopper also.
 Titrated using starch indicator at the end until the blue colour formed
disappears after thorough shaking with the stopper on.