When the drip method is used to check the air tightness of the device, an appropriate amount of wate

The use of a separating funnel should do: (1) Wash cleanly. (2) Check whether there is water leakage.

Check the piston of the funnel neck and the upper mouth plug of the funnel. Before the inspection, take out the stopcock core on the neck of the separating funnel, apply an appropriate amount of petroleum jelly (too much will clog the hole on the piston), insert it into the plug groove and rotate to make the oil film uniform and transparent, and rotate freely. Inspection Method:

Close the piston of the separating funnel, add an appropriate amount of water to it, and place the separating funnel on the iron ring of the iron frame; Connect a beaker below, open the glass plug on the upper mouth, or align the groove (or small hole) on the plug with the small hole on the funnel mouth, so that the gas in the separating funnel communicates with the atmosphere, about 1min, see if there is water leakage at the piston and neck, if it does not leak, rotate the piston 1800 and then observe for about 1min, if it still does not leak, the sealing performance of the piston is qualified. Close the upper mouth of the separating funnel, do it as shown in the figure, and open the piston, upright the separating funnel, rotate the plug of the upper mouth 1800, invert again, open the piston, observe for about 1min, if it still does not leak, the sealing performance of the upper mouth plug of the separating funnel is qualified.

When using a separating funnel, before releasing the liquid from the neck, it is necessary to open the glass plug on the upper mouth, or align the groove (or small hole) of the plug with the small hole in the funnel mouth, so that the gas in the separating funnel communicates with the atmosphere, otherwise the liquid will not flow out smoothly. When extracting and dispensing (the two are generally combined), it should also be noted: (1) the total volume of the liquid in the separating funnel should not exceed 2 3 of the volume of the separating funnel, and too much filling is not conducive to the mixing of liquid.

2) When shaking the liquid, the separating funnel should be inverted, which is conducive to the mixing of the liquid, and the separating funnel must be held according to the method shown in the figure, so as to avoid the piston or upper mouth plug of the separating funnel from loosening and leaking the liquid. (3) When the lower liquid is discharged, the tip of the separating funnel neck should be close to the inner wall of the container (such as a beaker) that accepts the liquid, so as to avoid the liquid from splashing; When rotating the live plug on the piston of the separating funnel, the piston on the piston should be pointed to the palm of the hand to prevent the live plug from coming out and leaking liquid; When the lower liquid happens to run out, close the piston immediately to prevent the upper liquid from flowing out. (4) The upper liquid should be poured out from the upper mouth of the separating funnel to prevent the two liquids from mixing again.

Wash the separating funnel after use. Wipe the stopcock of the separating funnel that is not used for the last time, and put a paper strip between the upper mouth and the plug, between the plug core (plug) and the plug groove to prevent the frost from sticking.

1. Use a separating funnel.

Method of checking the air tightness of the device: close the valve, put one end of the catheter in the water, and cover the Erlenmeyer flask with water.

After a period of time, if there are bubbles coming out of the catheter orifice in the water, the hand is released, and the water will flow backwards into the catheter orifice for a certain distance, which means that the air tightness is good;

2. Use the device of the long-neck funnel to check the air tightness

Method (1) clamp the catheter with a spring clamp, slowly add water to the long-necked funnel, the water forms a section of water column at the lower end of the long-necked funnel, and after a period of time, the water level of the water column will not drop, indicating that the air tightness is good.

Method (2) seal the lower end of the long-necked funnel with water, put the other end of the catheter into the water, cover the Erlenmeyer flask with your hand, after a period of time, if there are bubbles coming out of the catheter mouth in the water, release the hand, and the water will flow backward into the catheter mouth for a distance, indicating good air tightness; (The reason for sealing the lower end of the long-neck funnel is to prevent the gas from escaping from the long-neck funnel due to thermal expansion).

Leak. The separating funnel has a piston in the neck, which is an important reason why it is different from ordinary funnel and long neck funnel, because there is no piston in the neck of ordinary funnel and long neck funnel, and it cannot flexibly control the liquid. Before using the separating funnel, remove the stopcock core on the funnel neck and apply petroleum jelly, but not too much, so as not to block the flow hole. Insert the separating funnel into the plug groove and rotate to make the oil film uniform and transparent, and rotate freely.

Then close the, fill the funnel with water, check whether the is leaking, and the non-leaking separating funnel can be used. The amount of liquid added to the funnel should not exceed 3 4 of the volume. And it should not be filled with alkaline liquid.

To prevent impurities from falling into the funnel, the plug on the mouth of the funnel should be closed. When using, hold the funnel ball with the tiger's mouth with your left hand, and turn the piston with your thumb and index finger to control the dosing. At this time, the small groove of the glass plug should be aligned with the small hole on the side of the funnel mouth, so that the liquid can be added smoothly.

Before using a volumetric flask, the following two inspections should be performed:

1) Whether the volume of the volumetric flask is consistent with the requirements.

2) To check whether the cork is tight and does not leak. Put water in the bottle near the marking line, plug the cork tightly, make it upside down for 2min, and check it along the seam of the bottle mouth with a dry filter paper piece to see if there are water beads seeping out. If there is no leakage, rotate the plug 180°, plug it tightly, turn it upside down, and test whether there is leakage in this direction.

This double check is necessary because sometimes the stopper is not sealed in any position.

The index finger of the right hand is against the cork, the left hand holds the bottom of the bottle, turn the volumetric flask upside down to see if there is water seeping out at the mouth of the bottle, if not, rotate the stopper 180 degrees, repeat the above operation, if there is still no water seeping out at the mouth of the bottle, the volumetric flask does not leak.

The test of air tightness is based on the principle of pressure, which can close the separating funnel and judge the opening plug, move the syringe out to see that the syringe piston can be restored after stopping the force, and can also fix the syringe piston in the field, using the liquid level difference method, and the spine digging can also be used to increase the temperature method

Therefore, ab is chosen;

When using the separating funnel, the plug should be removed, so that the pressure in the separating funnel is equal to the atmospheric pressure, to ensure the smooth flow of liquid, open the separating funnel, and find that the liquid in it can not flow down, the possible reason is that the separating funnel cork is not opened (or the groove on the glass stopper is not aligned with the small hole on the funnel), so the answer is: the glass stopper on the neck of the separating funnel is not opened (or the groove on the glass stopper is not aligned with the small hole on the funnel);

When the flammable gas is mixed with oxygen to a certain extent, it will occur in case of open flame**, so the purity of the gas must be tested before the flammable gas is ignited, otherwise ** may occur, so the answer is: test the purity of the gas

The neck of the separating funnel is relatively short, and there is a piston at the lower end of the funnel, which can control the amount of liquid flowing out, and the separating funnel can be used for: 1. Solid-liquid or liquid-liquid reaction generation device.

Liquid addition, well control the amount of liquid added.

2. Substance separation and purification: the neck of the long neck funnel is relatively long and there is no piston, which is used in the gas generating device. When installing, insert the end of the long-neck funnel under the liquid surface to prevent gas from escaping from the long-neck funnel.

What you want to check is the gas generating device, one is a long-neck funnel, the other is a separating funnel, because the structure of the two funnel is different, so the inspection method is not the same.

The long-necked funnel itself does not have a piston, so it should be clamped --- water-stop clamp to the rubber tube, add water to the long-necked funnel until the difference between the internal and external liquid level is generated, and keep it unchanged for a period of time, that is, the air tightness is good.

The separating funnel itself has a piston, so it is --- to close the piston of the separating funnel, put the air duct into the water, slightly heat the Erlenmeyer flask, bubbles appear at the mouth of the air pipe, stop heating, and form a water column at the mouth of the air pipe, that is, the air tightness is good.

Since the separating funnel has a piston, controlling the piston can control the reaction, so there is no need for a water stop clamp.