How to use liquid reagents

(1) When taking liquid reagents from the dropper bottle, use the dropper in the dropper bottle. When using, first lift the dropper out of the liquid surface, squeeze the rubber head with your fingers to expel the air, then insert the dropper into the reagent, loosen your fingers to inhale the reagent.
When dropping the reagent into the test tube, you must clamp the dropper with your thumb, forefinger and middle finger, and hang it above the mouth of the test tube for dripping. Never put the dropper into the test tube or touch the wall of the tube, so as not to contaminate the dropper. Put the dropper back into the original dropper bottle after use, do not misplace it. The dropper containing the reagent should not be placed flat or the mouth of the tube should be inclined upward, so as to prevent the reagent from flowing into the rubber head, corroding the rubber head and contaminating the reagent.

(2) When taking liquid reagents from narrow-necked bottles, use the pouring method. First remove the bottle stopper, put it on the countertop, hold the container (such as test tube, measuring cylinder, etc.) in the left hand, and hold the label side of the reagent bottle with the right hand (so as not to contaminate the label when pouring the liquid), pick up the bottle and Gradually tilt the bottle so that the mouth of the bottle rests against the wall of the container, and slowly pour the reagent into the container, or along a clean glass rod into the beaker.
After pouring out the required amount, press the reagent bottle mouth against the container and slowly raise the bottle. In order to prevent the droplets left on the bottle mouth from flowing to the outer wall of the bottle. The excess reagent must not be returned to the original bottle.

(3) When measuring liquid reagents quantitatively, a graduated cylinder or a pipette can be used. You don’t need a graduated cylinder or pipette if you don’t need to take it accurately, just learn to estimate the amount of liquid you’ll get out of the bottle. For example, in the qualitative analysis experiment, a dropper is used to take the liquid, how many drops are in 1ml, and what fraction of the volume of the test tube is in 5ml. It is generally required that the amount of solution poured into the test tube does not exceed 1/3 of its volume.