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Why KI is added in redox iodometric titration even in the presence of sodium thiosulfate as a reducing agent?
Wiki User
∙ 14y ago
In iodometric titrations sodium thiosulfate is the titrant whereas the KI will reduce the analyte; eg: Cu2+ to Cu+. The I2 produced is then titrated by the sodium thiosulphate.
Cu2+ + I- --> CuI + I3-
I3- + 2 S2O32- ¾® 3 I- + S4O62-
To answer your question:
KI (reducing agent) is added to generate the iodine by the reduction of the analyte (Cu2+)
The formed iodine is then back-titrated with thiosulfate (titrant) to determine the amount of analyte originally present. As you can see the KI and sodium thiosulfate serve two different purposes.
KI improves solubility of Iodine
Wiki User
∙ 14y ago
KI is added in redox iodometric titration as an indicator because it reacts with iodine formed during the titration to form a starch-iodine complex, which gives a blue color. This color change helps detect the endpoint of the titration accurately. Sodium thiosulfate is used to titrate the excess iodine after the reaction with the analyte is complete.
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Difference between iodometry and iodimetry?
When an analyte that is a reducing agent is titrated directly with a standard iodine solution, the method is called "iodimetry". When an analyte that is an oxidizing agent is added to excess iodide to produce iodine, and the iodine produced is determined by titration with sodium thiosulfate, the method is called "iodometry".
Does the amount of potassium iodide added to the potassium iodate solution affect the amounts of iodine liberated in iodometric titration?
Yes, the amount of potassium iodide added to the potassium iodate solution in iodometric titration affects the amount of iodine liberated. Potassium iodide serves as a reducing agent, reacting with the iodate ion to form iodine. The quantity of potassium iodide added determines the rate and completeness of this reaction, impacting the amount of liberated iodine available for titration.
IF air oxidation of acid-iodide solution occurs what wiil happen to the iodometric titration?
If air oxidation occurs in an acid-iodide solution, iodide ions can be oxidized to elemental iodine by atmospheric oxygen. This can cause a loss of iodide ions, leading to inaccurate results in iodometric titration, which relies on the reaction between iodide ions and an oxidizing agent to determine the concentration of the analyte. To prevent this, the solution should be properly sealed to avoid exposure to air during the titration process.
What is the chemistry behind the redox titration?
Redox titration involves a reaction between an oxidizing agent and a reducing agent. During the titration, electrons are transferred from the reducing agent to the oxidizing agent, resulting in a change in oxidation states. The equivalence point is reached when the moles of the oxidizing agent are stoichiometrically equivalent to the moles of the reducing agent.
What is CaS2O3?
CaS2O3 is the chemical formula for calcium dithionite, which is a white crystalline compound used as a reducing agent in chemical reactions.
Why thiosulphate titration is called as redox titration?
Thiosulfate titration is called a redox titration because it involves a redox reaction between the thiosulfate (reducing agent) and the analyte (oxidizing agent). During the titration, the analyte oxidizes the thiosulfate while being reduced itself, resulting in a color change indicator that signals the equivalence point. This redox reaction is at the core of the titration process.
Why you use iodine in iodometric titration?
Iodine is used in iodometric titration as the titrant because it can easily react with reducing agents to form iodide ions. Its reaction with reducing agents leads to a change in color, making it useful for visual endpoint detection. This allows for the determination of the concentration of the reducing agent being analyzed in the titration process.
What is the difference between iodometric titration and iodimetric titration?
Iodometric titration involves the titration of iodine with a reducing agent, while iodimetric titration involves the titration of iodide with an oxidizing agent. In iodometric titration, iodine is detected by a starch indicator to determine the end point, while in iodimetric titration, iodide ion concentration is determined by titration with a standard solution of an oxidizing agent.
Why is it recommended to carryout iodometric titrations as quick as possible?
Iodometric titrations involve the titration of iodine with a reducing agent. Iodine is volatile and can escape into the air, which can lead to errors in the titration results. To minimize these errors, it is recommended to carry out iodometric titrations as quickly as possible to prevent the loss of iodine and ensure accurate results.
How is iodine librated in iodometric titration?
In an iodometric titration, iodine is liberated by the reaction between the analyte (substance being tested) and iodine solution. This reaction typically involves the reduction of a substance that releases iodine, which can then be titrated with a solution containing a reducing agent to determine the analyte concentration.
Difference between iodometry and iodimetry?
When an analyte that is a reducing agent is titrated directly with a standard iodine solution, the method is called "iodimetry". When an analyte that is an oxidizing agent is added to excess iodide to produce iodine, and the iodine produced is determined by titration with sodium thiosulfate, the method is called "iodometry".
Effect of oxidizing agents on iodometric titration?
Oxidizing agents can interfere with iodometric titration by oxidizing iodide ions to iodine prematurely, leading to an inaccurate measurement of the analyte's concentration. This interference can be minimized by adding a reducing agent to the titration solution to consume any excess oxidizing agent before reacting with the iodide ions. Additionally, careful selection of the titration conditions and proper sample preparation can help mitigate the effect of oxidizing agents on the titration results.
What is oxygen error in association with iodometric titrations what can you do to overcome?
Oxygen error in iodometric titrations occurs when oxygen in the atmosphere reacts with iodide ions, interfering with the titration results. To overcome this, the sample can be titrated in an inert atmosphere or by adding a reducing agent to remove the dissolved oxygen. Another approach is to boil the sample to remove the dissolved oxygen before titration.
Why iodometic titration is better than iodimetric titration?
Iodometric titration is better than iodimetric titration for the determination of reducing agents, as it directly measures the amount of oxidizing agent present. This method is more precise, as it involves the direct reduction of a known quantity of iodine to iodide ion. It is also less prone to interference from side reactions compared to the indirect measurement in iodimetric titration.
What is iodometry and iodimetry titration?
Iodometry is a quantitative analysis technique based on the measurement of the amount of iodine liberated in a chemical reaction, while iodimetry is a titration method that involves the use of iodine as a titrant to determine the concentration of an analyte in a sample. Iodometry is typically used to analyze reducing agents, while iodimetry is often employed in the analysis of oxidizing agents.
What is the effect of adding sulfuric acid in iodimetry titration?
Adding sulfuric acid in iodimetry titration helps to oxidize iodide ions to iodine, which is then titrated with a standard solution of sodium thiosulfate. Sulfuric acid also prevents the interference of other reducing agents that may be present in the sample being tested.
In iodometric titration how is iodine liberated either by oxidation or reduction?
In an iodometric titration, iodine can be liberated by either oxidation or reduction reactions. In oxidation, an oxidizing agent (such as H2O2) is added to oxidize iodide ions to iodine. In reduction, a reducing agent (such as sodium thiosulfate) is added to reduce iodine to iodide ions.
