Difference Between Supernatant and Precipitate

The key difference between supernatant and precipitate is that supernatant is in the liquid form, whereas precipitate is in the solid form.

Centrifugation is an analytical technique we use to separate particles from a solution. The separation can be done according to the size, shape, density or viscosity of these particles. In this process, we have to prepare a suspension and place it in a centrifuge tube, which is placed on a rotor to make it spin at a particular speed. At the end of the process, the particles will form a precipitate at the bottom of the centrifuge tube while the latter remains as a supernatant.

CONTENTS

1. Overview and Key Difference
2. What is Supernatant 
3. What is Precipitate
4. Side by Side Comparison – Supernatant vs Precipitate in Tabular Form
5. Summary

What is Supernatant?

The supernatant is the liquid we can observe above a solid precipitate. Sometimes, we call it a supernate as well. The techniques in which we can find the term supernatant are centrifugation, precipitation, crystallization, etc.

Usually, this liquid form is translucent. Furthermore, we can use this term to name the liquid that is above the sediments as well. The separation of the supernatant from the supernate-precipitate mixture is named as decantation.

What is Precipitate?

The precipitate is the solid form that deposits in a solution. It deposits at the bottom of the container because it is insoluble in the solution. A precipitate can form in different ways: from the reaction between two salts, by changing the temperature of a solution, by centrifugation, etc. However, the term precipitate is different from the term precipitant; a precipitate is the solid that forms from precipitation reaction while precipitant is the chemical species that causes a precipitate to form.

There are three major ways to separate a precipitate from the solution: filtration, centrifugation, and decantation. In the filtration process, we can filter the precipitate using filter papers or vacuum filtration to separate the liquid portion. In centrifugation, rapid rotation causes the suspended particles to form a precipitate at the bottom of the container. However, in the decantation process, what we do is pouring or suctioning the liquid away from the precipitate.

What is the Relationship Between Supernatant and Precipitate?

• Supernatant and precipitate are two related terms. Wherever a supernatant form, a precipitate also forms.

What is the Difference Between Supernatant and Precipitate?

The key difference between supernatant and precipitate is that the supernatant is in liquid form, whereas the precipitate is in solid form. Supernatant forms above the precipitate or sediment while the precipitate forms at the bottom of the container. Moreover, when considering the cause of formation, supernatant forms during centrifugation, crystallization, precipitation, etc. while the precipitate forms from the reaction between two salts, by changing the temperature of a solution, by centrifugation, etc.

Besides, a further difference between supernatant and precipitate is that we separate a supernatant mainly via decantation, whereas we can separate the precipitate from the reaction mixture using filtration, decantation, and centrifugation.

Summary – Supernatant vs Precipitate

In summary, the supernatant and precipitate are two related terms. Wherever a supernatant form, a precipitate also forms. However, the key difference between supernatant and precipitate is that supernatant is in liquid form, whereas precipitate is in solid form.

Reference:

1. Helmenstine, Anne Marie, “Supernate Definition in Chemistry.” ThoughtCo, Jan. 6, 2019, Available here.
2. Helmenstine, Todd. “Decantation Definition in Chemistry.” ThoughtCo, Aug. 6, 2019, Available here.
3. Helmenstine, Anne Marie. “Precipitate Definition and Example in Chemistry.” ThoughtCo, Jan. 3, 2019, Available here.

Image Courtesy:

1. “Chemical precipitation diagram” By Vectorized by ZooFari; raster by ZabMilenko – Own work based on Chemical precipitation diagram.png (Public Domain) via Commons Wikimedia
2. “Copper(I) Chloride Precipitate” By Brandon Burghardt -(Public Domain) via Commons Wikimedia