Iodometry is an indirect titration method whereas iodimetry is a direct titration method. This is the main difference between Iodometry and. Iodometry and iodimetry are two common titration methods useful in analytical chemistry. Iodometry is the quantitative analysis of a solution of. IODIMETRIC TITRATIONS When an analyte that is a reducing agent (like hypo) is titrated directly with a standard iodine solution, the method is called “iodimetry”.

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Overview and Key Difference 2. Formula for the determination of sulphur dioxide.

Iodometry – Wikipedia

Views Read Edit View history. In the food industry, iodometry is widely used to determine the concentration of hydroperoxides in any given lipid matrix oils and fats for human consumption. The free form either as a gas or an acid is the most important because it inhibits the action of microoganisms and acts as an antioxidant.

Then we should carry out another titration with the same mixture to determine the released amount of iodine. The reducing agent used does not necessarily need to be thiosulfate; stannous chloridesulfitessulfidesarsenic IIIand antimony III salts are commonly used alternatives.

Introduction to iodometric and iodimetric titrations a A reducing analyte b One reaction c Standard solution: Therefore, by determining the end point of the reaction, equations can be derived to obtain information of the stoichiometry and other necessary relationships between the reducing agent and Iodine which acts as the oxidizing agent in this case. Iodimetry is less common when compared to Iodometry.

I will talk, you will listen Titragion the lecture I will ask you some questions and at the end, you will do some tasks to check that you have understood the essential iodometroc. The addition of an excess of I 2 makes the solution turn dark ioometric indicating that all the sulphur dioxide in the sample has been titrated.

The iodine, which is stoichiometrically released after reduction of the analyte, is then titrated with ans standard sodium thiosulphate solution Na 2 S 2 O 3. The SO 2therefore, can combine with sugars, proteins and polyphenols. To a known volume of sample, an excess but known amount of iodide is added, which the oxidizing agent then oxidizes to iodine.


Here, the Iodine reduces to Iodide ions while the thiosulfate ions get oxidized further. Following reaction takes place when titrating. Iodometry is an indirect titration method whereas iodimetry is a direct titration method. Carrying out the titration 1 Erlenmeyer flask, source: Iodometry and Iodimetry Once sulphur dioxide is added to wine it does not remain free but oxidates in part and in part combines with other molecues:. This means that iodometrci reduction in the free form will result in a significant quantity of the combined form moving towards the free form.

The determination of arsenic V compounds is the reverse of the standardization of iodine solution with sodium arsenitewhere a known and excess amount of iodide is added to the sample:.

OK Predicting redox reactions Single replacement reactions we went over a few chapters ago are all redox reactions. Ioometric we will be looking at iodometric and iodimetric titrations, which are examples of redox titrations. For prolonged titrations, it is advised to add dry ice to the titration mixture to displace air from the erlenmeyer flask so as to prevent the aerial oxidation of iodide to iodine.

Share buttons are a little bit lower. Optical methods of analysis. Remember, we classify titrations according to the type of reaction between the titrant and the analyte.

You also know that an analyte is the substance being analyzed. Published by Juliana Lynch Modified over 3 years ago. Iodometry is commonly used to analyze the concentration of oxidizing agents in water samples, such as oxygen saturation in ecological studies or active chlorine in swimming pool water analysis. And a standard solution of this is used for the iodometric titrations. As you can see from the diagram, the titrant is usually delivered from a buret.

Then we can titrate the released iodine with another species. Iodometryalso known as iodometric titrationis a method of volumetric chemical analysisa redox titration where the appearance or disappearance of elementary iodine iovometric the end point. Application of iodometry One interesting application of iodometry in the food industry is for determining sulphur titratuon SO 2 in wine.


Sodium thiosulphate needs a neutral or weak acid environment to oxidise with tetrathionate in an xnd solution we would get sulphate oxidation ; 3. Introduction to iodometric and iodimetric titrations When a reducing analyte is titrated with iodine the titrantthe method is called iodimetry.

Colour titrtaion the starch solution in the presence of I2.

One interesting application of iodometry in the food industry is for determining sulphur dioxide SO 2 in wine. A direct titration with only 1 reaction: The number of equivalents of titrated iodine is the same as the number of hydroperoxides present in the sample as shown in the reaction in fig.

You will see gravimetry in other parts of the course. Strong light, nitrite and copper ions catalyzes the conversion of iodide to iodine, so these should be removed prior to the addition of iodide to the sample. A better, alternative method with higher accuracy is available, which involves the addition of excess but known volume of standard sodium arsenite solution to the sample, during which arsenic trisulfide is precipitated:.

Leave a Reply Cancel reply. Fisher Scientific; beaker, source: Introduction to iodometric and iodimetric titrations Slide 2: Introduction to iodometric and iodimetric titrations A reducing agent is the element or compound in a redox reaction that reduces another species.

Difference Between Iodometry and Iodimetry

In Iodimetric titrations, an Iodine solution is directly titrated with a reducing solution. The iodine content and thus the active chlorine content can be determined with iodometry.

Principles of the method The total sulphur dioxide in the wine sample is determined through direct iodimetric titration using starch as the indicator.

Sulphur dioxide has several important functions: To make this website work, we log user data and share it with processors.