Advantages and disadvantages of traditional chemical experiments

What are the advantages and disadvantages of conductometric titration? Please explain the shape of conductometric titration curve in this experiment as follows:

Advantages: All chemical reactions that can meet the above three conditions can be directly titrated. Direct titration is the most commonly used and basic titration method in titration analysis. For example, NaOH is titrated with HCl and Fe2+ is titrated with K2Cr2O7.

Disadvantages: direct titration cannot be done by redox method. However, if Ca2+ is precipitated into Ca2O3 _ C2O _ 4, filtered and washed, then dissolved with H2SO4 _ 4, and then C2O4 bound to Ca2+ is titrated with KMnO4 _ 4 standard solution, the content of calcium can be determined indirectly.

Precautions:

1, select an appropriate range to ensure that the instrument has been calibrated according to standard procedures before measurement.

2. Insert the electrode into the water sample, and the hole on the electrode must be immersed in water.

3. It is best to use plastic container to hold the water sample to be tested.

4. After high-purity water is put into the container, it should be determined quickly, otherwise the conductivity will increase rapidly, because carbon dioxide in the air will dissolve in water and become carbonate ions.

5, lofting container must be clean, no ion pollution, electrical conductivity is greatly affected by the temperature, every 65438+/-0℃, electrical conductivity increased by about 2%, generally stipulated that 25℃ is the standard temperature for determination.

Compared with general chemical titration, the advantages of potentiometric titration are as follows: general titration depends on the color change of indicator to indicate the titration end point. If the solution to be measured is colored or turbid, it is difficult to indicate the end point, or no suitable indicator can be found at all. Potentiometric titration indicates the titration end point through the sudden jump of electrode potential.