Praktikum Kimia Dasar Acara 7 : Ekstraksi Pelarut

Summary

This video provides a detailed demonstration of a chemistry lab experiment focused on solvent extraction. The primary goal is to separate fatty acids from soap using a solvent extraction method. The process involves several steps, including the preparation of materials such as aquades, petroleum ether, alcohol, and various laboratory equipment like separating funnels and analytical balances. Through titration and the use of indicators like phenolphthalein, the experiment aims to extract and measure the fatty acids content in different soap types, emphasizing the role of immiscible solvents and proper technique throughout the procedure.

Takeaways

• 😀 The goal of the experiment is to introduce chemical separation methods, specifically for extracting fatty acids from soap and determining the fatty acid content using solvent extraction.
• 😀 The materials used in the experiment include aquades, NaCl, petroleum ether, 90% alcohol, phenolphthalein indicator, and various soaps (Dettol, Johnson baby soap, Lux).
• 😀 Key equipment for the experiment includes a separating funnel, beakers, pipettes, analytical balance, glass rods, a heating element, and other standard laboratory tools.
• 😀 The soap is carefully measured at 0.25g using an analytical balance and cut with a cutter before being dissolved in aquades to prepare for extraction.
• 😀 The soap solution is mixed with petroleum ether in a separating funnel to separate the fatty acids, forming two distinct layers due to the difference in density (similar to oil and water).
• 😀 The experiment requires careful handling of petroleum ether, which evaporates quickly, so steps must be taken to avoid losing it during the process.
• 😀 The two layers formed in the separating funnel are separated by draining the aqueous soap layer through the funnel, while the petroleum ether layer is kept for further processing.
• 😀 After multiple extractions with petroleum ether, the solution is tested for the presence of soap using phenolphthalein as an indicator. A pink color indicates soap is still present, while no color change means the soap has been removed.
• 😀 The next step involves adding alcohol to the petroleum ether solution to help dissolve the fatty acids, followed by titration using NaOH to determine the amount of fatty acid present.
• 😀 The final titration results are recorded after the NaOH is added until a color change occurs, which marks the completion of the process and indicates the fatty acid content.

Q & A

What is the objective of the experiment described in the script?

The objective of the experiment is to introduce the method of solvent extraction to separate fatty acids from soap and to determine the fatty acid content using this method.

What are the main chemicals used in the extraction process?

The main chemicals used are aquades (distilled water), NaCl (1 molar solution), petroleum ether, 90% alcohol, and phenolphthalein as an indicator.

How much soap is initially weighed for the experiment?

0.25 grams of soap is weighed using an analytical balance for the experiment.

Why is phenolphthalein added during the extraction process?

Phenolphthalein is added to the solution to detect the presence of soap. If soap is still present, the solution turns pink, indicating that the extraction was not fully completed.

What is the role of petroleum ether in the experiment?

Petroleum ether is used to extract fatty acids from the soap solution due to its immiscibility with water. It forms a separate layer on top of the aqueous solution, which can be removed after extraction.

What happens during the extraction when petroleum ether and soap solution are mixed?

When petroleum ether and the soap solution are mixed, two distinct layers form: the top layer is petroleum ether containing the extracted fatty acids, while the bottom layer is the aqueous soap solution.

What is the purpose of using NaOH during the titration step?

NaOH is used in the titration step to determine the fatty acid content in the extracted petroleum ether. The amount of NaOH required to neutralize the fatty acids helps calculate their concentration.

Why is it important to handle petroleum ether carefully during the experiment?

Petroleum ether is volatile and evaporates quickly, so it must be handled carefully to prevent loss. The containers holding petroleum ether should be sealed to prevent it from evaporating.

What is the significance of the two distinct layers formed in the separation funnel?

The two distinct layers—petroleum ether on top and the aqueous soap solution below—indicate that the two substances are immiscible due to differences in their densities. This immiscibility is crucial for separating the fatty acids from the soap.

How do you know when the extraction process is complete?

The extraction process is considered complete when no pink color remains after adding phenolphthalein to the solution, indicating that all soap has been removed and the fatty acids have been successfully extracted.