Separation of the Mixture of Solid Unknowns
In the chemical world, vital substances are not always in pure separated forms. In order to obtain desired solid compounds from a mixture, the process of extraction becomes quite useful. This experiment used the process of extraction to separate a mixture of two unknown solid compounds. The unknown solid mixture was composed of a carboxylic acid and a neutral organic compound. These two solids were separated by acid-base extraction.
Once the two solids were separated, they were characterized by the crude melting point range of temperatures.
Extraction was the primary technique used in this experiment. Many common organic solvents do not mix with water, and extraction takes advantage of this property. Chemical reactivity of functional groups in the organic solvents alters solubility. This was caused in the lab experiment with acid-base reactivity. The solution that contained organic compounds in an organic solvent was extracted with an aqueous acid or aqueous base solutions.
In addition to aqueous acids and bases, sodium chloride was used to decrease solubility of organic compounds in order to make extraction more efficient and complete. This process is called salting out. Another tool that was used in this lab was a separatory funnel. This instrument was used to separate two immiscible solvents through shaking and swirling. The solvent with the higher density separated to the bottom and the solvent with the lower density was on top in the separatory funnel.
After the completion of the experiment, many laboratory techniques were conducted. In review, an acid-base extraction using a separatory funnel was demonstrated. An organic liquid was was dried, and isolated solid product was separated by vacuum filtration and simple distillation. These procedures may have been performed in a laboratory as practice for real world applications.
Lab techniques such as distillation can...
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