Pembuatan Larutan Standar Titrasi Alkalimetri

Summary

This video demonstrates the process of preparing a standard sodium hydroxide solution for alkalimetry titration. It begins with the accurate weighing of sodium hydroxide crystals, dissolving them in distilled water, and transferring the solution into a 100 mL measuring flask. The video then covers the standardization of the sodium hydroxide solution using oxalic acid, involving precise weighing, mixing, and titration with a phenolphthalein indicator. The titration continues until a color change from colorless to pink is observed, ensuring the correct concentration of the sodium hydroxide solution for future experiments.

Takeaways

• 😀 The experiment focuses on preparing a standard solution for alkalimetry titration.
• 😀 Tools required include a weighing bottle, Erlenmeyer flask, dropper, glass stirrer, spatula, beaker, measuring flask, burette, stand, and clamp.
• 😀 The main materials needed are oxalic acid, sodium hydroxide (NaOH), distilled water, and phenolphthalein indicator.
• 😀 The first step involves preparing a 0.1 normal sodium hydroxide solution by weighing 0.4 grams of NaOH crystals using a weighing bottle.
• 😀 Sodium hydroxide crystals are hygroscopic, so the balance and equipment should be checked and cleaned before use.
• 😀 After weighing the NaOH, it is dissolved in distilled water (about 10 mL) and then transferred into a 100 mL measuring flask.
• 😀 The flask is filled with distilled water up to the mark and the solution is shaken to ensure homogeneity.
• 😀 The next step is to standardize the sodium hydroxide solution using oxalic acid.
• 😀 To do this, 0.126 grams of oxalic acid is weighed on a watch glass and added to a 250 mL Erlenmeyer flask.
• 😀 The burette is filled with the NaOH solution, ensuring it is bubble-free and the meniscus is at zero.
• 😀 The oxalic acid solution is titrated with NaOH, and the endpoint is reached when the color changes from colorless to pink due to the phenolphthalein indicator.

Q & A

What is the main objective of the experiment in the transcript?

The main objective of the experiment is to prepare a standard solution of sodium hydroxide (NaOH) for alkalimetry titration and to standardize this solution using oxalic acid.

What are the tools and materials required for this experiment?

The tools and materials required include a weighing bottle, a 250 ml Erlenmeyer flask, a dropper, a glass stirrer, a spatula, a 100 ml beaker, a 100 ml measuring flask, a burette, a stand and clamp, oxalic acid, sodium hydroxide (NaOH), distilled water, and phenolphthalein (pp) indicator.

Why is a weighing bottle used for measuring NaOH crystals?

A weighing bottle is used to measure NaOH crystals because sodium hydroxide is hygroscopic, meaning it absorbs moisture from the air. The weighing bottle helps to prevent moisture absorption and ensures accurate measurement.

How much NaOH is weighed for the preparation of the standard solution?

0.4 grams of NaOH crystals are weighed for the preparation of the standard solution.

What is the first step in preparing the sodium hydroxide solution?

The first step is to weigh 0.4 grams of NaOH crystals using a weighing bottle. The balance is checked and cleaned before use to ensure accurate weighing.

How is the NaOH solution prepared once the crystals are weighed?

After weighing the NaOH crystals, they are placed in a 100 ml beaker, and approximately 10 ml of distilled water is added. The solution is stirred until the NaOH crystals dissolve.

What happens after the NaOH solution is dissolved in the beaker?

Once the NaOH solution is dissolved in the beaker, it is transferred to a 100 ml measuring flask. The beaker is rinsed with distilled water, and the solution is made up to the mark on the measuring flask using distilled water, then shaken until homogeneous.

What is the purpose of standardizing the NaOH solution with oxalic acid?

The NaOH solution is standardized with oxalic acid to determine its exact concentration, ensuring that it is correctly prepared for titration in alkalimetry experiments.

How much oxalic acid is used in the titration process?

0.126 grams of oxalic acid are weighed for the standardization process.

What is the role of the phenolphthalein indicator in the titration?

Phenolphthalein (pp) indicator is added to the oxalic acid solution to indicate the endpoint of the titration. The color changes from colorless to pink, signaling that the titration is complete.