1. Test the acidity and alkalinity of the solution with test paper: Check the acidity and alkalinity of the solution with a common pH test paper. Place a small piece of test paper on a dry and clean drip plate, then use a glass rod to draw the solution to be tested, drop it on the test paper, observe the color change of the test paper, and compare the color of the test paper with the color of the standard color plate. The pH of the solution.

PH test papers are divided into two categories: one is a wide range of pH test papers, the color change range is PH=1-14, which is used to roughly check the pH value of the solution; the other is precision PH test paper, which is used for more accurate test solution. PH value, there are many types of precision test strips, which can be selected according to different needs. The change in a wide range of pH test strips is 1 PH unit, while the precision PH test strip changes less than one PH unit.

2. Test the gas with test paper: commonly used PH test paper or litmus paper to check the acidity and alkalinity produced by the reaction. Wet the test paper with distilled water and apply the test paper to the tip of the clean glass rod. Place the test paper on top of the test tube and observe the change in the color of the test paper.