Question

Determine the molarity of the given KMnO$_4$ solution with the help of supplied oxalic acid solution by volumetric analysis method.

Hint:

Ensure you use fresh oxalic acid solution and maintain a steady titration speed to prevent errors.

Answer 1

Aim.
To determine the molarity of the given KMnO$_4$ solution using oxalic acid solution by volumetric analysis.
Apparatus.
Burette, conical flask, pipette, Bunsen burner, test tube, H$_2$SO$_4$, oxalic acid solution.
Procedure.
1. Fill the burette with the KMnO$_4$ solution.
2. Prepare a known volume of oxalic acid solution in the conical flask.
3. Add a few drops of dilute H$_2$SO$_4$ to the flask to provide H$^+$ for the reaction.
4. Titrate the KMnO$_4$ solution into the oxalic acid solution while stirring continuously.
5. A persistent pink color will appear near the endpoint. This indicates that the reaction is complete.
6. Note the volume of KMnO$_4$ used.
Calculation.
Using the equation: \[ M_1V_1 = M_2V_2 \] Where: - \(M_1\) = Molarity of KMnO$_4$ - \(V_1\) = Volume of KMnO$_4$ used in titration - \(M_2\) = Molarity of oxalic acid solution - \(V_2\) = Volume of oxalic acid solution used in titration Since the balanced reaction between KMnO$_4$ and oxalic acid is: \[ 2MnO_4^- + 5C_2H_2O_4^{2-} \rightarrow 2Mn^{2+} + 5CO_2 + 8H_2O \] The molar ratio between KMnO$_4$ and oxalic acid is 2:5.