Definition - What does Precipitate mean?
A precipitate is an insoluble solid that emerges from a liquid solution. The process of making precipitate is called precipitation. Often the precipitate emerges as a suspension.
Precipitation reactions can be used in:
- Making pigments
- Removing salts from water in water treatment
- Classical qualitative inorganic analysis
- Isolation of the products of a reaction during workup
In metallurgy, precipitation from a solid solution is also a useful way to strengthen alloys; this process is known as solid solution strengthening.
Precipitation causes heightened corrosion.
Corrosionpedia explains Precipitate
Precipitation is the creation of a solid in a solution or inside another solid during a chemical reaction or by diffusion in a solid. When the reaction occurs in a liquid solution, the solid formed is called the precipitate.
Precipitate is referred to as a pellet after sedimentation when using a centrifuge to press it into a compact mass. The precipitate-free liquid remaining above the solid is called the supernate or supernatant. Powders derived from precipitation are known as flowers.
Precipitates can form when:
- Two soluble salts react in solution to form one or more insoluble products
- Temperature of a solution is lowered - The lower temperature reduces the solubility of a salt, resulting in its precipitation as a solid. The chemical that leads the solid to form is called the precipitant.
- Using a supersaturated solution - Without sufficient force of gravity (settling) to bring the solid particles together, the precipitate remains in suspension.
- Antisolvent is added - This radically drops the solubility of the desired product. Subsequently, the precipitate may easily be separated by filtration/decanting or centrifugation.
Precipitate development is valuable in the detection of the type of cation in a salt. For example, a barium nitrate solution will react with sulfate ions to form a solid barium sulfate precipitate, indicating that it is expected that sulfate ions are present. Precipitation reactions are also useful to extract elements, like magnesium, from seawater.
Properties of precipitates include:
- Insoluble ionic solid products of a reaction
- Reactions dependent on temperature or on solution concentration
- Solids produced in precipitate reactions are crystalline and can be suspended as sediment
- The two parts of supernatant liquid (precipitate and supernate) can be separated
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