Separation funnel

November 1, 2021

It is an instrument used to separate heterogeneous mixtures, especially those that unite oil and water or those immiscible solutions. With the separation funnel we can empty the first liquid as soon as we notice that the second liquid is about to fall.

What is it?

It is a glass container, it is shaped like an inverted pear or cone. It has a drain that allows the liquids to be separated out into a lower container. The flow is regulated by a valve located at the bottom of the funnel.

At the top of the funnel we will find a frosted glass opening that can be sealed with a lid. Through this opening we will load the funnel with immiscible or insoluble liquids.

The funnel is used to separate immiscible liquids through the difference in densities and properties that these liquids possess. This allows them to separate into two or more parts depending on the elements joined in the mix.

You can find it in presentations ranging from 125 ml, 250 and up to 1 L. You can find them with a conical or inverted pear shape, the stopcock will always be in the narrowest part.

You can also find funnels with a straight or cylindrical shape, in these cases the mouth has a frustoconical section that allows closure through a glass or plastic stopper. The gasket is made of ground glass to ensure watertightness.

How is it used?

The most common shape of separating funnels is the conical shape, also called an inverted pear shape, with the stopcock or stopcock in the narrowest part.

To use it you must make sure that it is very clean, that the joint or stopcock is closed and pour the mixture inside. Allow time for the immiscible liquids to clearly separate into two or more fractions.

At this point open the tap and let the liquid drain, which will be the densest, into a flask or beaker. Observe carefully and when you notice that the union of both liquids approaches the valve, close the flow of liquid. In this way, the denser liquid will remain in the flask and the less dense in the funnel.

If you want to continue separating liquids (if the mixture has several immiscible substances) you will only have to change the flask or the beaker.


It is usually widely used in chemistry organizes to extract the solute from one solvent and pass it to another, this phenomenon is known as extraction.

The partition coefficient is known as the concentrations of a solute dissolved in two solvents that are immiscible and that are in contact and equilibrium. Through these data it is possible to carry out the extraction of the solute.

In general, the aqueous phase is the most dense and therefore it is in the lower phase, the organic substance usually has a lower density and will be in the upper phase. Keep in mind that when chlorinated solvents are used, they will be located in the lower part and water in the upper part, as they are much denser.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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