Praktikum Analisis Kuantitatif : Titrasi Alkalimetri

Summary

In this practical session, students learn about quantitative analysis through acid-base titration. The primary objective is to determine the content of salicylic acid in a sample using an alkalimetric method. The process begins by neutralizing 96% ethanol with NaOH to ensure accuracy, followed by the preparation of a sample containing salicylic acid. The titration involves adding NaOH to the sample until it reaches a pink endpoint, indicating the neutralization point. The session emphasizes precise measurement, methodical procedures, and the importance of using neutral solvents to ensure correct results.

Takeaways

• 😀 The practice focuses on determining the salicylic acid content in a sample using alkalimetric titration.
• 😀 The first step involves neutralizing 96% ethanol with NaOH to prevent the acid properties of ethanol from affecting the result.
• 😀 A sample containing salicylic acid (0.25g) is weighed and prepared for titration.
• 😀 The titration process uses NaOH solution to determine the salicylic acid content in the sample.
• 😀 The equipment used in this practice includes burette, pipette, glass beakers, Erlenmeyer flask, stir bar, and indicator solutions.
• 😀 Phenolphthalein is used as an indicator during titration, and the solution turns pink when neutralization occurs.
• 😀 The ethanol solution must be neutralized first to avoid interference with the titration process.
• 😀 After preparing the ethanol, the salicylic acid sample is dissolved in neutralized ethanol before starting the titration.
• 😀 The titration continues until the solution reaches a pink color that remains steady, indicating the endpoint.
• 😀 The final volume of NaOH required for neutralization is recorded to calculate the salicylic acid concentration in the sample.

Q & A

What is the main focus of the practical session described in the transcript?

The main focus of the practical session is the quantitative analysis of salicylic acid in a sample using acid-base titration (alkalimetri).

Why is it important to neutralize the 96% ethanol before starting the titration process?

It is important to neutralize the 96% ethanol because it is slightly acidic, and using it without neutralization could affect the accuracy of the salicylic acid analysis.

What are the key materials and equipment used in this experiment?

Key materials include salicylic acid sample, phenolphthalein indicator, 96% ethanol, 0.1 N NaOH, and distilled water. Key equipment includes burettes, pipettes, Erlenmeyer flasks, stirring rods, and analytical balance.

What is the purpose of using phenolphthalein as an indicator in the titration?

Phenolphthalein is used as an indicator because it changes color when the solution shifts from acidic to neutral, signaling the end point of the titration process.

How is the ethanol neutralized before the titration?

Ethanol is neutralized by adding a drop of 0.1 N NaOH until the solution turns pink, indicating that the ethanol has become neutral.

What is the significance of measuring 250 mg of the sample?

Measuring 250 mg of the salicylic acid sample ensures that a precise amount is used for the titration, allowing for accurate determination of the acid's concentration.

What is the purpose of adding water to the ethanol-salicylic acid mixture during the titration?

Water is added to help dissolve the salicylic acid, which is not soluble in ethanol alone, thus facilitating the titration process.

What does the appearance of a pink color in the solution indicate during titration?

The appearance of a pink color indicates that the titration has reached the endpoint, where the solution has been neutralized.

How much NaOH was used to determine the salicylic acid concentration in the sample?

Approximately 16.6 mL of 0.1 N NaOH was used to determine the concentration of salicylic acid in the sample.

Why is it necessary to carry out the filtration process during the experiment?

The filtration process is necessary to ensure that any impurities or undissolved particles are removed from the solution before the titration, ensuring the accuracy of the results.