4. In Part IIA , a student uses 0.020061 M KMnO4 to titrate a sample containing

Question

4. In Part IIA, a student uses 0.020061 M KMnO4 to titrate a sample containing oxalate ions, C2O42-:

5C2O42- + 2MnO4- +16H+ --------> 10 CO2 + 2 Mn2+ + 8 H2O

These data were obtained:

- initial buret reading: 1.38 mL KMnO 4   

- final buret reading: 14.78 mL KMnO4

A) Show a complete calculation of how you determine the number of moles of C2O42- ions that reacted with the MnO% in the KMnO4 solution.

B) What would happen if,
-KMnO4 is added too rapidly?

-Oxalate solution is not swirled sufficiently?

- Oxalate solution is not hot enough?

Explanation / Answer

Answer for B

If KKMnO4 is added fastly it cannot compete the reaction with oxalic acid solution as it is the slow reaction. Moreover when it doesn't react then pink colour remains as such in solution and hence pre matured end point occurs which leads to error in analysis.

If oxalate solution is not swirled sufficiently, the same will occur as in the above.

Oxalate solution if not heated properly the reaction being occurred slowly.

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