Operation and use of glass instruments commonly used in volumetric flasks

It is mainly used to prepare solutions of accurate concentration.
Before using a volumetric flask, check: whether the volume of the volumetric flask is consistent with the required volume; if preparing a solution of substances that are easily decomposed by light, a brown volumetric flask should be selected; whether the ground stopper or plastic stopper is leaking.

1. Leak test:
Add tap water to the vicinity of the marking line, close the stopper tightly, hold the stopper with your index finger, turn the bottle upside down for 2 minutes, and use dry filter paper to check for water seepage along the gap of the bottle mouth. If there is no water leakage, rotate the cork 180°, and then stand upside down for 2 minutes to check.
2. Notes:
A glass rod must be used when transferring the solution to the volumetric flask;
Do not hold the bottle with your hands to avoid liquid expansion;
When the volume in the volumetric flask reaches about 3/4, shake the volumetric flask for a few weeks (do not turn it upside down) to mix the solution initially, then put the volumetric flask on the table, slowly add water to about 1cm close to the marking line, etc. For 1-2min, the solution adhering to the inner wall of the bottle neck is left, and water is added until the lowest point under the meniscus is tangent to the marking line;
The hot solution should be cooled to room temperature before being injected into the volumetric flask, otherwise it may cause volume error;
The volumetric flask cannot store solutions for a long time, especially lye, which will corrode the glass and cause the stopper to stick and cannot be opened;
After the volumetric flask is used up, rinse it with water;
If it is not used for a long time, clean the grinding mouth and dry it, and put it on a piece of paper.