P9 Penentuan Kandungan Kalsium dalam Sampel Air Menggunakan Metode Kompleksometri

Summary

This virtual practical session guides viewers through the process of determining calcium levels in water samples using the complexometric titration method. The experiment involves standardizing a 0.01 M EDTA solution and performing titrations to assess water hardness and calcium content. With the use of indicators like EBK and murexide, participants follow detailed steps to mix solutions, titrate, and observe color changes. By the end of the experiment, viewers will understand how to measure calcium and magnesium ions in water samples, while also learning the significance of each procedural step.

Takeaways

• 😀 The virtual experiment focuses on determining the calcium content in water using complexometric titration.
• 😀 The hosts of the video are Kakbah Ishartono and Kak Juliana, who guide viewers through the entire process.
• 😀 The experiment requires various reagents including EDTA (0.01 M), calcium carbonate, Murexide indicator, and pH buffer.
• 😀 Personal protective equipment (PPE) such as gloves, masks, and lab coats are essential for safety during the experiment.
• 😀 The first procedure involves standardizing the EDTA solution by titrating it with calcium carbonate solution.
• 😀 The titration process is conducted by adding EDTA drop by drop to the solution, while swirling the Erlenmeyer flask.
• 😀 The endpoint of the titration is marked by a color change from purple to blue, indicating the completion of the titration.
• 😀 Accurate volume recording of EDTA used is crucial for calculating the calcium content in the sample.
• 😀 The second procedure determines the hardness of water by titrating a water sample with the standardized EDTA solution.
• 😀 The final procedure is aimed at determining the calcium content in the water sample using Murexide as an indicator and NaOH to adjust pH.
• 😀 The titration in the final procedure ends when the solution changes from red to purple, signifying the completion of the calcium determination.

Q & A

What is the purpose of this virtual laboratory experiment?

The purpose of the experiment is to determine the calcium concentration in a water sample using the complexometric method, specifically through titration with an EDTA solution.

What materials are required for this experiment?

The materials required for the experiment include EDTA 0.01 molar, calcium carbonate 0.01 molar solution, pH buffer 10, murexide indicator, EBK indicator, sodium hydroxide 0.1 molar, and water samples from the laboratory tap.

Why is EDTA used in this experiment?

EDTA (Ethylenediaminetetraacetic acid) is used in this experiment because it is a chelating agent that binds to calcium ions, forming a stable complex. This allows for the measurement of calcium concentration through titration.

What is the role of the pH buffer in the titration process?

The pH buffer helps maintain the proper pH level during the titration process, ensuring that the EDTA effectively binds to the calcium ions. A pH of around 10 is typically optimal for this reaction.

How do you standardize the EDTA solution?

To standardize the EDTA solution, you pipet 20 mL of calcium carbonate solution into an Erlenmeyer flask, add EBK indicator, and then titrate with EDTA until the solution changes from purple to blue. This process allows for the accurate determination of the EDTA concentration.

What does the color change from purple to blue signify in the titration?

The color change from purple to blue indicates that all the calcium ions in the solution have reacted with the EDTA. This marks the end point of the titration.

Why is it important to repeat the titration process twice?

Repeating the titration process twice ensures that the results are reliable and accurate. It helps identify any discrepancies and allows for more consistent data.

What is the significance of using two different indicators (EBK and murexide)?

The two indicators serve different purposes: EBK is used for the standardization of EDTA, while murexide is used for the titration of calcium ions in the water sample. Each indicator provides a distinct color change to signal the completion of the titration process.

How is the calcium concentration determined in the water sample?

The calcium concentration is determined by titrating the water sample with the standardized EDTA solution. The amount of EDTA required to reach the endpoint (color change) is used to calculate the concentration of calcium ions in the sample.

What is the final color change expected when titrating the calcium sample?

During the titration of the calcium sample, the color of the solution changes from red to purple, indicating that the reaction is complete and the amount of calcium in the sample has been determined.