Iodometry & Iodimetry

It's a simple presentation on Iodometry & Iodimetry.

1. WELCOME TO PRESENTATION Iodometry & Iodimetry

2. In Iodometric titration , an oxidation agent is allowed to react in neutral medium or in acidic medium ,with excess of potassium iodide to liberate free iodine . Iodometry is a n indirect titration. Free iodine is titrated against a standard reducing agent. Usually, a standard thiosulphate solution is used for this. the method is called "iodometry". Iodometry

3. The first step is done by the reaction between the oxidizing agents (K 2 Cr 2 O 7 ) and KI (excess) Thus the iodine is quickly liberated. KI + Oxidizing agent → I 2 K 2 Cr 2 O 7 + 6KI + 7H 2 SO 4 → Cr 2 (SO 4 ) 3 + 4K 2 SO 4 + 7H 2 O + 3I 2 Iodometry

4. The liberated iodine (in first step) is titrated with standard solution of sodium thiosulphate. Starch is used as indicator. At the end point, All iodine will react with thiosulphate and produce iodide ion . The Indicator don’t show any reaction with iodide ion. Then, the blue or violet color of starch indicator disappears. Iodometry

5. Iodimetry

6. These are the titration in which free iodine is used. When an analyte that is a reducing agent is titrated directly with a standard iodine solution, the method is called " I odimetry". Iodine is mixed with potassium iodide and KI 3 solution is prepared. KI+I 2 → KI 3 Starch can be used as an indicator in iodimetric titrations too. I 2 + reducing agent → 2 I -

7. Iodine is a weak oxidant and it can be reduced by the reductants . I 2 2I - I 2 + I - I 3 - KI K + + I - Strong reducing agent Sn 2+ + I 2 Sn 4+ + 2I - 2S 2 O 3 2- + I 2 S 4 O 6 2- + 2I - Weak reducing agent As 3+ + I 2 As 5+ + 2I - Sb 3+ + I 2 Sb 5+ + 2I -

8. Titrate the above solution by using analyte solution present in the burette. I 2 + 2S 2 O 3 2- S 4 O 6 2- + 2I - At the equilibrium point all iodine will react with sodium thiosulphate and the blue color disappears. I - + Indicator No Reaction (Colorless)

9. Iodine is very useful in titration method These methods are used to determine the concentration of vitamin-C, sodium thiosulphate, amount of copper in super conductor etc. Determining the concentration of these chemicals is important because hydroperoxides have a negative effect on the acceptability of the fat matrix used

10. Thank You