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”. involve the potentiometric titration of aqueous iodine with sodium thiosulfate the analyte (a reducing agent) reacts with iodine to produce iodide: iodimetry. Titrations Fajans Preciptation Complexometric. Fact File 1: Introduction to iodometric and iodimetric titrations. Quantitative Classical Chemical Analysis. Titrations.

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Thiosulphate is added until the blue colour disappears and the solution turns colourless. Exactly, the tiitrations classical quantitative chemical analysis is gravimetry. Titration involving iodine commonly uses a starch suspension as indicator. Istituto comprensivo di Tubirgo.

Available chlorine refers to chlorine liberated by the action of dilute acids on hypochlorite. One interesting application of iodometry in the food industry is for determining sulphur dioxide SO 2 in wine. The titration reaction can be represented as:.

Examples include the determination of copper IIchlorateHydrogen peroxideand dissolved oxygen:. Redox titration using sodium thiosulfateNa 2 S 2 O 3 usually as a reducing agent is known as iodometric titration since it is used specifically to titrate iodine. Titrant KMnO4 2 Dichromatometric: This is one difference between iodometry and iodimetry.

Iodometry – Wikipedia

However, it is more common to use Iodometric methods for analysis rather than Iodimetric methods. Introduction to iodometric and iodimetric titrations In this lesson: Now, in order to be able to quantify the analyte, we need the analyte to react with a substance of a known concentration. The standard solution is Iodine I2 On the other hand in iodometric titrations: Share buttons are a little bit lower.

Together with reduction potential of thiosulfate: This is performed in the presence of a starch indicator to make it easier to recognize the end point. The iodine, which is stoichiometrically released after reduction of the analyte, is then titrated with a standard sodium thiosulphate solution Na 2 S 2 O 3.


Difference Between Iodometry and Iodimetry

The iodine content and thus the active chlorine content can be determined with iodometry. 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:.

The excess arsenic trioxide is then determined by titrating against standard iodine solution using starch indicator. Titations and hydrogensulfites reduce iodine readily in acidic medium to iodide. The half-reaction is titrstions follows:. In iodometry, iodides react with another oxidizing agent in an acidic medium or neutral medium.

Hydroperoxides in the presence iodijetric KI reduce as shown in the redox reaction below. Sulphur dioxide has several important functions: Examples of reducing agents: Reaction of radicals responsible for formation of hydroperoxides in edible fats and oils. The turning point indicates that all the iodine released has been titrated.

Iodimetry The term iodimetry, on the other hand, refers to titration using an iodine solution and is useful for determining substances that have reducing properties.

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. Once the bond between the iodine I 2 and the helical chain of beta-amylose is formed it turns an intense blue.

Iodometry and Iodimetry, Daniele Naviglio « Analytical Chemistry « Agraria « Federica e-Learning

Introduction to iodometric and iodimetric titrations An oxidaizing agent is the element or compound in a redox reaction that oxidaizes another species. This is the main difference between Iodometry and Iodimetry. Although the sulfide content in sample can be determined straight forwardly as described for sulfites, the results are often poor and inaccurate.

What are the four types of titrations?

The half-reaction is as follows: To a known volume of sample, an excess but known amount of iodide is added, which the oxidizing agent then oxidizes to iodine. Today we will be looking at iodometric and iodimetric titrations, which are examples of redox titrations. Instrumental Chemical Analysis Furthermore, another difference between iodometry and iodimetry is that, in iodometry, iodides titraitons with another oxidizing agent in an acidic medium or neutral medium while in iodimetry, it uses free iodine to undergo titration with a reducing agent.


The basis of titration is a reaction between the analyte and a standard reagent known as the titrant. Colour of the starch solution in the presence of I2. In Iodometric titrations, the Iodine which has been produced as a result of a previous redox reaction is been titrated with a reducing agent such as thiosulfate ions. A definition of the word titration is: My presentations Profile Feedback Log out.

Exam 2 on Wed, Nov 3. We have left redox titrations iodometric now, because you needed to be familiar with the other three type of titrations. The term iodimetry, on the other hand, refers to titration using an iodine solution and is useful for determining substances that have reducing properties. Although the two terms iodometry and iodimetry sound similar, they are two different techniques we use in analytical chemistry. Forms of SO 2 in wine Once sulphur dioxide is added to wine it does not remain free but oxidates in part and in part combines with other molecues: For analysis of antimony V compounds, some tartaric acid is added to solubilize the antimony III product.

Starch granules stained with iodine — through microscope. The most important thing in this presentation is for you to understand the differences between iodometric and iodimetric titrations.