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Why is it that during titration of iodine or triiodine with thiosulphate the starch indicator should not be added until near the end point?
The Starch-Iodide complex is not very soluble in water, so the starch is added near the endpoint of an Iodine titration, when the Iodine concentration is low. This eliminates errors due to the fact that some Iodine may remain adsorbed on the complex and go undetected.
so if you add the starch indicator only right near the end point when the solution is a light yellow colour the starch shouldn't complex and go lumpy.
What else can I help you with?
What is the reason of heating solution during redox titration?
This is far to be a rule for this titration.
Why is a small amount of indicator added during titration?
An indicator shows when we have added just enough of the second reagent to react with the first. If you mean why do we add only a small amount of indicator, it is to keep the answer accurate. Some of the reagent is used changing the indicator so the answer is always slightly bigger than perfection, and the more indicator you add, the larger the error.
During titration a student adds water to the beaker with the acid Will this affect the results?
Adding water to the beaker with the acid during titration will dilute the acid solution, potentially altering the concentration and thus affecting the results. It is important to maintain the initial concentration of the acid solution throughout the titration process for accurate results.
Why KI is added in redox iodometric titration even in the presence of sodium thiosulfate as a reducing agent?
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
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.
Indicator used during the standardization of sodium thiosulphate?
Starch
What is the indicator in titration reactions that turns pink in basic solutions?
Phenolphthalein is the indicator that turns pink in basic solutions during titration reactions.
Why thiosulphate titration is called as redox titration?
A thiosulfate titration is mostly carried out to determine the amount of iodine present in the solution. In these reactions, thiosulfate ion acts as the reducing agent. This types titrations are often called as 'iodometric titrations'.
Why is important that the indicator is present in the solution during the course of titration?
the reason why a indicator is important in some titration is to show a change in the solution. for example as a solution runs from acidic to basic the indicator may turn a different color. but this is the reason why it is important inmost experiments.
Why you add starch at the end of titration?
Starch is added at the end of titration as an indicator to signal the endpoint of the reaction. It forms a complex with the iodine produced during the titration, resulting in a color change from clear to blue-black, indicating that the titration is complete.
What is the indicator use in potentiometric titration?
The indicator used in potentiometric titrations is typically a pH electrode. By measuring changes in pH during the titration process, the endpoint of the titration can be determined accurately. The pH electrode provides a continuous measurement of the solution's pH, allowing for a precise determination of the equivalence point.
Why is phenolpthalein used as the indicator for the assay of tartaric acid?
Phenolphthalein is used as an indicator during the titration of tartaric acid because the pH at which phenolphthalein changes color (around pH 8.2-10) is close to the equivalence point of the titration of tartaric acid with a strong base like NaOH. This makes it a suitable indicator for detecting the endpoint of the titration when the acid has been completely neutralized by the base.
What is the use of platinum electrode in potentiometry titration?
Platinum electrode is used as the indicator electrode in potentiometry titration to measure the potential difference between the indicator electrode and the reference electrode. It provides a stable and reproducible potential during the titration process, allowing for accurate determination of the equivalence point. Platinum electrodes are inert and do not participate in the redox reactions happening during the titration, making them suitable for a wide range of titrations.
Why should a constant amount of indicator be used in a titration?
Indicators are weak acid. Too much will alter the titre
In HCl and NaOH titration which indicator is used?
Phenolphthalein is commonly used as an indicator in the titration of hydrochloric acid (HCl) with sodium hydroxide (NaOH). Phenolphthalein changes color from colorless to pink at the endpoint of the titration when all the acid has been neutralized by the base.
What happens during an acidic base titration in the presents of an indication?
During an acid-base titration, an indicator is added to the solution to determine the endpoint, which is when the moles of acid are equal to the moles of base. The indicator changes color at the endpoint, indicating the completion of the reaction. This color change helps in identifying the point of neutralization and determining the concentration of the unknown solution.
What is meant by External Indicator used in titration?
An external indicator in titration is a substance that is added in small amounts to the analyte solution during titration to signal the endpoint of the reaction. It changes color at or near the equivalence point, making it easier for the observer to detect when the reaction is complete. Common examples of external indicators include phenolphthalein and methyl orange.
