Proper use of pH probe and storage method of pH meter probe
There are errors in the measurement of pH meter and pH test paper when measuring pH value in experiments. This article focuses on the measurement error of pH acidometer and pH test paper during the experiment. In the experiment, dilute sulfuric acid and sodium hydroxide were used to adjust the deionized water (which does not contain any substances). When it was adjusted to 8, the pH test paper was used to measure 6. However, the buffer solution was measured to be 9.18 using pH test paper. The color was correct. Use a pH meter. 9.18 The buffer solvent is also correct. What's going on? It's just that many people may not use a pH meter and pH test paper at the same time to test the pH below 3 and above 8. There is definitely no problem with the test paper.
Problems with the practical operation of pH meters: Enthusiastic netizens have mentioned that technicians and production staff in some units feel that pH meters are difficult to use, troublesome to use, and the data is inaccurate. Since we use it frequently, the pH standard solution has a short validity period. People in the unit are accustomed to using single-color pH test paper, which is more accurate and easier to control than a pH meter in actual operation. There are also three-color test paper, but the quality is very poor. I have used foreign five-color pH test paper, and the solution is well dispersed on it and the color development is also very clear.
Some netizens also mentioned that pH meters are inaccurate, and so are pH test strips. Let’s see what kind of sound there is below.
Answers to the above questions. Enthusiastic netizens mentioned that the pH test paper measured the buffer solution as 9.18. I think there is a problem with this statement. It is impossible to measure the pH to two decimal places with pH test paper. It does not have such high accuracy. It is just a rough measurement. If you want accurate pH during the experiment, then I think it is better to use a pH acidity meter. As for why it is inaccurate when adjusting deionized water but accurate when measuring buffer solutions, there are many reasons;
1. It is possible that the mixture is not evenly mixed;
2. There may be something wrong with the test strip. Wait. This netizen thinks this is not the main problem. In short, in a word, if you want accurate values, you should use a pH meter to measure it.
