chemical indicator的意思|示意

'

Chemical indicators are substances that can be used to detect the presence or absence of a certain substance in a solution. They are also used to measure the pH of a solution. Chemical indicators are often used in titration experiments and to detect the presence of certain chemicals in a solution.

The most common type of chemical indicator is a universal indicator, which is a combination of several indicators. Universal indicators can be used to determine the pH of a solution and to detect the presence of certain chemicals. A universal indicator usually consists of indicators that range from red to blue in color. Each color is related to a specific pH value. For example, if a solution is red, it usually indicates a pH value of 1; if it is yellow, it usually indicates a pH value of 7; and if it is blue, it usually indicates a pH value of 14.

Chemical indicators can also be used to determine the endpoint in titration experiments. In this case, one drop of indicator is added to the solution and the color change is observed. The endpoint is reached when the color of the solution changes to a predetermined value. This is usually the color that is associated with the titrant used in the experiment.

In conclusion, chemical indicators are used to determine the presence or absence of certain chemicals in a solution, to measure the pH of a solution, and to determine the endpoint in titration experiments. They are very useful in analytical chemistry, as they provide quick and accurate results.