Praktikum Kimia Dasar Part 5 Asidi Alkalimetri

Introduction

This tutorial provides a comprehensive guide on performing acid-base titration experiments, specifically focusing on the determination of the concentration of acidic solutions, particularly oxalic acid. Following this step-by-step guide will enhance your understanding of basic chemistry principles and practical laboratory skills.

Step 1: Prepare Your Equipment and Materials

Before beginning your experiment, gather all necessary equipment and materials to ensure a smooth process.

Required Materials

• Burette
• Pipette
• Conical flask
• Beakers
• Acid solution (known concentration)
• Oxalic acid solution (unknown concentration)
• Indicator solution (e.g., phenolphthalein)
• Distilled water
• White tile (optional, for better visibility)

Practical Tips

• Ensure all glassware is clean and free from contaminants to prevent errors in your measurements.
• Familiarize yourself with the operation of the burette and pipette for accurate dispensing.

Step 2: Set Up the Titration

Setting up correctly is crucial for accurate results.

Procedure

1. Rinse the burette with the titrant (the known acid solution) and fill it, ensuring no air bubbles are present.
2. Rinse the pipette with the oxalic acid solution and use it to measure a specific volume (usually 25 mL) into the conical flask.
3. Add a few drops of the chosen indicator to the oxalic acid solution in the flask.

Common Pitfalls

• Do not forget to record the initial volume of the titrant in the burette before starting the titration.
• Be careful not to overshoot the endpoint; the color change indicates the completion of the reaction.

Step 3: Conduct the Titration

This step involves the actual titration process to determine the concentration of the unknown solution.

Procedure

1. Slowly add the known acid solution from the burette to the oxalic acid solution while constantly swirling the conical flask.
2. Watch for a color change in the solution, which indicates that the endpoint of the titration is near.
3. As the endpoint approaches, add the titrant dropwise until you observe a sustained color change.

Practical Tips

• Record the final volume of the titrant in the burette immediately after reaching the endpoint.
• Repeat the titration process at least three times for accuracy and take the average of your results.

Step 4: Calculate the Concentration

Once you have your titration results, you can calculate the concentration of the unknown solution.

Calculation Formula

Use the formula: [ C_1V_1 = C_2V_2 ] Where:

• ( C_1 ) = concentration of the acid solution (known)
• ( V_1 ) = volume of the acid solution used
• ( C_2 ) = concentration of the oxalic acid solution (unknown)
• ( V_2 ) = volume of the oxalic acid solution used

Example Calculation

If you used 0.1 M hydrochloric acid (HCl) with a volume of 20 mL to titrate 25 mL of oxalic acid, the calculation would look like this: [ 0.1 , \text{M} \times 20 , \text{mL} = C_2 \times 25 , \text{mL} ] Solve for ( C_2 ) to find the concentration of the oxalic acid.

Conclusion

In this tutorial, you learned how to perform acid-base titrations to determine the concentration of acidic solutions. Key takeaways include the importance of careful measurement, accurate execution of the titration process, and understanding the calculations involved. For further practice, consider repeating the experiment with different acids or concentrations. Happy experimenting!