Table of Contents
- 1 How is iodine liberated in iodometric titration?
- 2 Why is iodine used in iodometric titration?
- 3 What happens during redox titration?
- 4 What is the basic difference between iodometric and Iodimetric titration?
- 5 What’s the difference between iodometric and iodimetric titration?
- 6 When is equivalent amount of iodine liberated in iodometry?
How is iodine liberated in iodometric titration?
The principle is that iodine is liberated by adding sulphuric acid to a solution of iodised salt. Potassium iodide solution is added to keep the iodine in the dissolved state. Iodine liberated is titrated with sodium thiosulphate solution to form sodium iodide and sodium tetrathionate.
Why is iodometric titration a redox reaction?
Iodometric titration as mentioned above is a titration method which also occurs in a redox reaction. This sodium thiosulfate is also known as a reducing agent to titrate the iodine. From this process, you can find out the concentration of the oxidizing agent in the solution being tested.
What is used as reducing agent in iodometric titration?
Starch: In iodometric titration, sodium thiosulphate, Na2S2O3 (a reducing agent) is used specifically to titrate iodine.
Why is iodine used in iodometric titration?
Iodometry is used to determine the concentration of oxidising agents through an indirect process involving iodine as the intermediary. In the presence of iodine, the thiosulphate ions oxidise quantitatively to the tetrathionate ions.
What is the role of sodium thiosulfate in iodometric titration?
Iodometry is used to determine the concentration of oxidizing agents through an indirect process involving iodine as a mediator. In the presence of iodine, thiosulphate ions are quantitatively oxidized to tetrathionate ions.
How do you do iodometric titration?
Add to Erlenmeyer flask 50 mL of demineralized water, 10 mL of sulfuric acid solution, 10-15 mLs of potassium iodide solution, and two drops ammonium molybdate solution. Titrate with 0.1 N sodium thiosulfate to faint yellow or straw color. Swirl or stir gently during titration to minimize iodine loss.
What happens during redox titration?
When the oxidation-reduction reactions happen in a titration method, it is known as a redox titration. In this technique, transfer of electrons occurs in the reacting ions present in the aqueous solutions during the chemical reaction. This is further classified on the basis of reagent used in the redox titration.
What is the principle of redox titration?
The principle involved in the oxidation-reduction titrations is that the oxidation process involves the loss of electrons whereas the reduction process involves the gain of electrons.
Which titration is used in the iodometric process?
In an iodometric titration, a starch solution is used as an indicator since it can absorb the I2 that is released. This absorption will cause the solution to change its colour from deep blue to light yellow when titrated with standardised thiosulfate solution.
What is the basic difference between iodometric and Iodimetric titration?
Complete answer:
| Iodometric Titrations | Iodimetric Titrations |
|---|---|
| Unlike iodometry, it is an indirect titration method. | It is a direct titration method. |
| Here the total number of redox reactions is two. | Here the number of redox reactions is one. |
How does sodium thiosulfate react with iodine?
Sodium thiosulfate is used to reduce iodine back to iodide before the iodine can complex with the starch to form the characteristic blue-black color. Once all the thiosulfate is consumed the iodine may form a complex with the starch. Potassium persulfate is less soluble (cfr.
What is end point in iodometric titration?
The indicator that is usually chosen for titrations involving iodine (triiodide) is starch. Starch forms a dark blue complex with iodine. The end point in iodimetry corresponds to a sudden color change to blue. Likewise the end point in iodometry corresponds to a sudden loss of blue color due to the complex.
What’s the difference between iodometric and iodimetric titration?
In iodimetry, it uses free iodine to undergo titration with a reducing agent. Note that iodometry involves indirect titration of iodine liberated by reaction with the analyte, whereas iodimetry involves direct titration using iodine as the titrant. Both involve iodine, but as you will see there are some differences.
What happens to iodine in oxidation reduction titration?
Oxidation reduction titration Iodine dissolves in the iodide-containing solution to give triiodide ions, which have a dark brown color. This titrating species is a standard solution of a reducing agent, which is capable of reducing iodine back to iodide form.
How is iodometry used in redox titration?
Iodometry is one of the most important redox titration methods. Iodine reacts directly, fast and quantitively with many organic and inorganic substances. Thanks to its relatively low, pH independent redox potential, and reversibility of the iodine/iodide reaction, iodometry can be used both to determine amount of reducing agents
When is equivalent amount of iodine liberated in iodometry?
In iodometry, an equivalent amount of iodine is liberated when the given sample of an oxidizing agent oxidizes potassium iodide in an acidic medium, for example : the determination of cupric sulphate (CuSO4) :
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