Precautions for the use of Burette Stopcock

1. During titration, the left hand is not allowed to leave the piston, and the solution is allowed to flow down by itself.

2. During titration, the gaze should focus on the color change in the Erlenmeyer flask, do not pay attention to the scale change, and ignore the progress of the reaction.

3. Generally, each sample should be titrated three times in parallel, each time starting from the zero line, and each time should be recorded on the experimental record form in time, and it is not allowed to record to other places.

4. Precautions for using basic burettes

(1) The direction of force should be flat to avoid the glass beads moving up and down.

(2) Do not pinch the lower part of the glass bead, otherwise it may cause air to enter the tip of the tube to form bubbles.

(3) Do not exert excessive force during the process of squeezing the hose to avoid the solution flowing out too quickly.

5. Titration can also be carried out in a beaker, the method is the same as above, but stirred with a glass rod or electromagnetic stirrer.