[biospy]

We have:

2MnO4(-) + 5H2C2O4+ 6H(+)--> 2Mn(2+)+10 CO2+ 8 H20


Now we did a titration figured that with a .030 KMnO4 solution 15 mL we were given got a .035 M H2C2O4 15 mL(oxalic acid)

Now the challenge:

Imagine the oxalic acid being contaminated with samples of each of the following salts. Which of the following would ADVERSELY affect the titration results? Explain

1. Na2SO4

2. NaCl

3. KNO3

I'm not sure what to do...I figure 3 won't since K is a spectator and all..could be wrong...just need help and will give 10 points right away. I don't know what we are looking for in this.....would I need to write completely new equations for each or what? I'm so lost!

[Dan]

MnO₄^- is a strong oxidising agent. It is oxidising oxalic acid your titration.

If there is another species present that can be oxidised by MnO₄^-, then your results will be affected adversely.

So, you need to find out whether Na⁺, K⁺, SO₄^2-, Cl^- or NO₃^- will be oxidised by MnO₄^-. If you're not sure, I suggest consulting a table of reduction potentials which can be found in the appendicies of Inorganic and pysical textbooks, or a data book, or on the internet.