Abstract:
The experiment aims to standardize the given solution of KMnO4 and calculate the volume required for preparing 1 dm3 of 0.01M KMnO4 solution volumetrically.
Introduction:
Potassium permanganate (KMnO4) is a strong oxidizing agent commonly used in titrations to determine the concentration of reducing agents. In this experiment, the given solution of KMnO4 will be standardized using a primary standard substance, typically oxalic acid (H2C2O4). The volume of KMnO4 solution required to prepare a 0.01M solution will be determined using volumetric analysis.
Procedure:
- Dilute the given solution of KMnO4 to a known volume in a volumetric flask.
- Prepare a standard solution of oxalic acid by accurately weighing a known mass of oxalic acid dihydrate and dissolving it in distilled water in a volumetric flask.
- Add dilute sulfuric acid (H2SO4) to both the KMnO4 and oxalic acid solutions to provide the acidic medium required for the reaction.
- Titrate the standardized KMnO4 solution against the standard oxalic acid solution using a burette until a color change is observed.
- Record the initial and final burette readings to determine the volume of KMnO4 solution used in the titration.
- Calculate the molarity of the standardized KMnO4 solution and use it to calculate the volume required to prepare 1 dm3 of 0.01M KMnO4 solution.
Observations and Calculations:
Initial burette reading = \( V_0 \) mL
Final burette reading = \( V_1 \) mL
Volume of KMnO4 solution used = \( V_1 - V_0 \) mL
Molarity of KMnO4 = \( \frac{{\text{{Molarity of oxalic acid}} \times \text{{Volume of oxalic acid solution used in titration}}}}{{\text{{Volume of KMnO4 solution used in titration}}}} \)
Volume of KMnO4 solution required for 0.01M solution = \( \frac{{0.01 \times 1000}}{{\text{{Molarity of KMnO4 solution}}}} \) mL
Conclusion:
The KMnO4 solution has been successfully standardized, and the volume required for preparing 0.01M KMnO4 solution volumetrically has been determined.
Precautions:
- Ensure accurate measurement of volumes using pipettes and burettes.
- Avoid contamination of solutions and glassware.
- Perform titration carefully to ensure accurate results.
- Use appropriate safety measures when handling chemicals.
- Calibrate equipment before use.
Short Questions
- What is the chemical formula of potassium permanganate?
Answer: KMnO4 - Why is it necessary to standardize KMnO4 solution?
Answer: To determine its exact concentration accurately. - What primary standard substance is commonly used for the standardization of KMnO4 solution?
Answer: Oxalic acid (H2C2O4) - What indicator is typically used in the titration of oxalic acid with KMnO4?
Answer: Potassium permanganate (KMnO4) - What color change indicates the endpoint of the titration?
Answer: Faint pink color persists. - Why is dilute sulfuric acid added to the oxalic acid solution during titration?
Answer: To acidify the solution and provide suitable conditions for the reaction. - What is the volume of KMnO4 solution required to prepare 1 dm3 of 0.01M KMnO4 solution?
Answer: Depends on the concentration of the standardized solution, which is determined through titration. - What precaution should be taken to ensure accurate measurement of volumes during the experiment?
Answer: Use calibrated glassware. - What is the role of KMnO4 in the titration?
Answer: It is the titrant, used to react with the analyte (oxalic acid). - What is the stoichiometry of the reaction between oxalic acid and KMnO4?
Answer: Balanced chemical equation representing the reaction between the two substances. - How is the endpoint of the titration determined?
Answer: When a color change occurs, indicating the completion of the reaction. - What is the purpose of titrating the oxalic acid solution with KMnO4?
Answer: To determine the concentration of the oxalic acid solution. - What is the typical color of potassium permanganate solution?
Answer: Purple. - Why should solutions be handled with care during the experiment?
Answer: To prevent accidents and ensure safety. - What volume of oxalic acid solution is typically used in the titration?
Answer: A known volume, usually measured with a pipette. - What is the importance of using a primary standard substance in the standardization process?
Answer: Primary standard substances offer high purity and stability, ensuring accurate results. - What is the unit of concentration commonly used for KMnO4 solutions?
Answer: Molarity (M). - Why is it important to avoid contamination of solutions?
Answer: Contamination can affect the accuracy of results and lead to erroneous conclusions. - What is the significance of recording initial and final burette readings during titration?
Answer: To calculate the volume of KMnO4 solution used in the titration. - What is the concentration of the standardized KMnO4 solution after standardization?
Answer: Determined through calculations based on the titration results.
Multiple Choice Questions (MCQs)
- What is the color change observed at the endpoint of the titration?
Answer: b) Pink to colorless - Which of the following is NOT a precaution to be taken during the experiment?
Answer: d) Heating solutions rapidly - What is the unit of concentration typically used for KMnO4 solutions?
Answer: a) Molarity (M) - What is the role of sulfuric acid in the titration?
Answer: c) To prevent oxidation of KMnO4 - Which apparatus is used to deliver precise volumes of solutions in the experiment?
Answer: a) Pipette