Titrasi Oksidimetri : Permanganometri dan Bikromatometri ( Kelompok 2 )

Summary

This video provides an in-depth guide to redox titration techniques, specifically permanganometry and bichromatometry. The presenters, Muhammad Iqbal Rata, Rahman Usman, and Siti Fadilah, explain the theory behind titration using potassium permanganate (KMnO₄) as a standard solution, its standardization process with oxalic acid (H₂C₂O₄), and the chemical reactions involved. They cover the preparation of oxalic acid solutions, the titration procedure, and calculations to determine the concentration of KMnO₄. This tutorial offers clear insights into laboratory practices for performing these titrations, ideal for students and practitioners in chemistry.

Takeaways

• 😀 Titration permanganometry is a type of redox titration that uses potassium permanganate (KMnO4) as a standard solution.
• 😀 The standardization of KMnO4 commonly uses oxalic acid (H2C2O4) as a reactant, where KMnO4 oxidizes H2C2O4, and KMnO4 itself undergoes reduction.
• 😀 The reduction of MnO4- to Mn2+ is balanced by adding 4 molecules of H2O on the right side to balance the oxygen atoms.
• 😀 The oxidation of oxalate (C2O4^2-) to CO2 is balanced by adding 2 electrons on the right side to match the charges on both sides.
• 😀 The half-reactions in a redox titration are balanced by electrons to ensure charge conservation.
• 😀 The procedure for standardizing KMnO4 includes the use of a balance, a 250 mL volumetric flask, and Erlenmeyer flasks, along with other standard lab equipment.
• 😀 During titration, the potassium permanganate solution is carefully added to the oxalic acid solution until the color change occurs, signaling the endpoint.
• 😀 The procedure for preparing 0.1 M oxalic acid involves calculating the mass of oxalic acid required for a given volume and molarity, then dissolving it in distilled water.
• 😀 In the titration process, potassium permanganate is added to a solution of oxalic acid, and sulfuric acid is used to maintain the acidic environment for the reaction.
• 😀 The reaction between KMnO4 and oxalic acid can be expressed as 2MnO4- + 18H+ + 5C2O4^2- → 2Mn2+ + 4H2O + 10CO2, which forms the basis for determining concentrations of KMnO4 and H2C2O4 in the experiment.

Q & A

What is permanganometry?

Permanganometry is a type of redox titration where potassium permanganate (KMnO₄) is used as the titrant to determine the concentration of a substance through oxidation and reduction reactions.

What role does potassium permanganate play in the titration?

Potassium permanganate (KMnO₄) acts as an oxidizing agent in the titration, where it is reduced while oxidizing the oxalic acid (H₂C₂O₄).

What is the standard procedure for preparing the oxalic acid solution?

To prepare a 0.1 mol/L oxalic acid solution, 3.5 g of oxalic acid is weighed and dissolved in distilled water to make a final volume of 250 mL.

Why is sulfuric acid added during the titration?

Sulfuric acid is added to create an acidic environment necessary for the reaction, ensuring the proper reduction of potassium permanganate and oxidation of oxalic acid.

How is the endpoint of the titration identified?

The endpoint of the titration is identified when the solution turns a faint pink color, indicating that all the oxalic acid has been reacted and the potassium permanganate is no longer being reduced.

What are the key half-reactions involved in the titration?

The half-reactions involved are the reduction of potassium permanganate (MnO₄⁻ to Mn²⁺) and the oxidation of oxalic acid (C₂O₄²⁻ to CO₂).

How are the half-reactions balanced?

The half-reactions are balanced by ensuring the number of electrons in both the oxidation and reduction reactions are equal. For the reduction of KMnO₄, 5 electrons are involved, while for the oxidation of oxalic acid, 2 electrons are involved.

What are the materials needed for the titration?

The materials required include potassium permanganate (KMnO₄), oxalic acid (H₂C₂O₄), sulfuric acid, distilled water, and various laboratory equipment like an analytical balance, buret, volumetric flask, Erlenmeyer flask, and glass stirrers.

What is the formula to calculate the concentration of KMnO₄ after the titration?

The concentration of KMnO₄ can be calculated using the formula: Cₖₘₙₒ₄ = (2 × Vₓₓₓ × Cₓₓₓ) / (5 × Vₖₘₙₒ₄), where V is the volume and C is the concentration of oxalic acid (H₂C₂O₄) and KMnO₄.

What is the chemical equation for the titration reaction?

The balanced chemical equation for the titration reaction is: 2MnO₄⁻ + 16H⁺ + 5C₂O₄²⁻ → 2Mn²⁺ + 8H₂O + 10CO₂.