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Potentiometric titrations are based on standard electrode potential change observed through potentiometer. But direct titrations are based on physical observation on color change by a human. In other words the detection of the endpoint can be noted from significant change in the voltage or millivoltage value in the case of potentiometric titration. So both precision and accuracy can be achieved in potentiometric titration.
But in the case of direct titration using an indicator, change in the color is the criteria and the observation of color change can vary from one person to other and so both precision as well as accuracy cannot be achieved. For instance in an acid-base titration using methyl orange indicator, the color change observation is significantly vary from person to person.
Moreover in potentiometric titration the equivalence point (different from end point and equivalence point is more accurate than end point) can be noted from a second derivative graph. So pinpoint accuracy over the titration results can be accomplished in a potentiometric titration.
By
Dr M Kanagasabapathy PhD
Asst. Professor in Chemistry,
Rajus' College, Affiliated to Madurai Kamaraj University,
Rajapalayam (TN) India 626 117
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LaoPotentiometric titration allows for precise endpoint detection based on changes in voltage, making it more accurate than direct titration methods. It is also more versatile and can be used for titrations where there is no visible endpoint or for titrations involving colored or turbid solutions. Additionally, potentiometric titration can offer a wider dynamic range and better reproducibility compared to direct titration methods.
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What is the advantage of potentiometric titration?
Potentiometric titration allows for a direct measurement of the equivalence point without the need for a visual indicator. It provides precise and accurate results, especially for complexometric reactions or when indicators may interfere with the reaction.
What are the disadvantages of potentiometric titration?
Some disadvantages of potentiometric titration include the need for specialized equipment such as a pH meter or ion-selective electrode, which can be costly. Additionally, it may require a skilled operator to perform the titration accurately and interpret the results correctly. Potentiometric titration can also be slower compared to other titration methods.
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 potentiometric titration curves are s-shaped?
Potentiometric titration curves are s-shaped due to the buffering capacity of the solution. At the beginning of the titration, minimal change in pH occurs as the solution acts as a buffer, resisting pH changes. Once the buffer region is overcome, the titration curve becomes steeper as the solution approaches the equivalence point.
What is a potentiometric titration?
Potentiometric titration is a technique used to determine the concentration of an analyte in a solution by measuring the potential difference between two electrodes in the solution. It involves adding a titrant solution of known concentration to the analyte solution until the equivalence point is reached, where the two solutions react completely. The equivalence point is determined by the inflection point on the titration curve, and the concentration of the analyte can be calculated from this data.
