Significance of measuring conductivity: Pure water cannot conduct electricity, and there is basically no pure water of 100%. Water can conduct electricity because it contains some electrolytes such as salts, which are divided into strong electrolytes and weak electrolytes. The ionization degree of weak electrolyte is related to equilibrium constant, concentration and ionization degree.

Similarly, for strong electrolytes, according to the empirical formula summarized by Kohlrausch, it can be seen that the conductivity of the solution is also related to the concentration. Therefore, by measuring the conductivity, the concentration of electrolyte contained in the solution can be calculated indirectly, so as to know the content of electrolyte in water. The water quality can be preliminarily judged by conductivity, and then different water treatment schemes can be adopted.

Extended data:

Matters needing attention in measuring water conductivity:

1. The electrode should be selected correctly according to the conductivity range of the water sample: if the conductivity of the measured solution is < 10 us/cm, use a bright platinum electrode; When the conductivity of the measured solution is in the range of 10 ~ 40 us/cm, platinum black electrode is used;

2. It is best to immerse the platinum black electrode in water before and after use to prevent the platinum black from inerting. When measuring, there should be no bubbles on the electrode surface. If the electrode coated with platinum black is found to be out of order, it can be immersed in 10% HNO3 or HCl solution for 2 minutes, and then washed with water before use;

3. The conductivity increases with the increase of temperature. When the temperature rises by 65438 0℃, the electrical conductivity increases by 2% ~ 2.5%. Generally speaking, 25℃ is the standard temperature for measuring electrical conductivity.

Baidu encyclopedia-conductivity

Baidu encyclopedia-conductivity tester