1. Potentiometric titration can be used to titrate colored or turbid solutions at first. Ordinary titration depends on the change of indicator color to indicate the titration end point. If the solution to be measured is colored or turbid, or there is no or lack of indicator, it is difficult to indicate the end point, or no suitable indicator can be found at all.
2. Potentiometric titration can also be used to dilute test solution or incomplete titration reaction.
3. Potentiometric titration has high sensitivity and accuracy, and can realize automatic continuous determination.
4. Potentiometric titration is widely used, which can be used for neutralization titration (acid-base titration), precipitation titration, complexometric titration and redox titration.
Extended data
The indicator electrode of potentiometric titration is different in different applications.
Indicator electrode is a PH glass electrode used in acid-base titration, and indicator electrode can be made of platinum electrode in redox titration. In complexometric titration, if EDTA is used as titrant, mercury electrode can be used as indicator electrode; in precipitation titration, if halide ion is titrated with silver nitrate, silver electrode can be used as indicator electrode.
In the process of titration, with the constant addition of titrant, the electrode potential e changes constantly. When the electrode potential suddenly jumps, it means that the titration has reached the end point. Differential curve is easier to determine the titration end point than ordinary titration curve. If the automatic potentiometric titrator is used, the titration curve can be drawn automatically, the titration end point can be found automatically, the volume can be given automatically, and the titration is fast and convenient.
In the process of potentiometric titration, the reference electrode and indicator electrode are inserted into the measured solution to form a working battery. With the addition of titrant, due to chemical reaction, the measured ion concentration is constantly changing, and the indicator electrode potential is also changing. A potential mutation occurs near the equivalence point. Therefore, the titration end point can be determined by measuring the change of electromotive force of the working battery.
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