First, what is the effect of bubbles in the burette to the test results?
1. If there is a bubble at the beginning, it is equivalent to displaying more liquid than the actual one (because the gas is supported), so the volume of the final titration solution is too large, and the concentration of the liquid to be calculated is too large.
2. If there is a bubble at the end, it is equivalent to displaying more liquid than the actual one (because the gas is supported). After the head and tail data are subtracted, the calculated volume of the titration solution is smaller than the actual use. This results in a small concentration of the test solution.
If the bubble persists and the volume does not change, there is no effect on the titration, but the bubble volume tends to change, so there are bubbles in the burette that cannot be ignored.
Method for discharging bubbles in alkali burette
The alkaline burette should bend the hose upwards and squeeze the glass beads hard to spray the solution from the tip to remove air bubbles. The bubbles in the basic burette are generally hidden near the glass beads, and it is necessary to check whether the bubbles in the hose are completely exhausted. If you always feel that the bubbles are difficult to discharge, you should consider whether the tip of the burette is not cleaned under the piston. Try to wash it with acid soaking.
Method for discharging bubbles in acid burette
First ensure the inner wall of the tube below the piston, without adhering to the obvious Vaseline, fill the burette, quickly open the cock, usually a few times, you can solve the problem, of course, you can also try to tilt the burette. The amount of solution in the bubble fashion should not be too small, so that the solution should have a certain impulse when the piston is opened, and the speed of opening the piston should be faster. If you always feel that the bubbles are difficult to discharge, you should consider whether the tip of the burette is not cleaned under the piston. Try to wash it with acid soaking.
Should you have any inquiries, do not hesitate to get in touch with WUBOLAB, the laboratory glassware manufacturer.
