reaction formula

[somayeh932]

I want to titrate soil containing manganese oxide using the titration method in the presence of sodium oxalate, sulfuric acid, and water, with permanganate as the titrant, to determine its purity. Can you help me write the reactions and balanced reactions?

[Benzene]

Hello somayeh932!

Balanced reaction:
MnO₂ + MnO₄^- + H^+ → Mn^2+ + 8 H₂O + O₂ + 2 H₂O + e-

Charge Balance:

MnO₂: Mn^4+ (charge: +4)
MnO₄^-: Mn^7+ (charge: +7), O^2- (charge: -2) =>
total charge: +5
H^+: +1
Mn^2+: +2
8 H₂O: neutral
O₂: neutral
2 H₂O: neutral
To balance the charge, we need to add more electrons to the right side of the equation. We can do this by adding 1 (one) electron to the Mn^2+ ion:
This ensures the conservation of both mass and charge.

Bye,
Benzene

[ChenBeier]

Equation is wrong. Charges not balanced.
Only half equation have electrons. A balanced one has no.

And the method is different. First a known excess amount of oxalate react with MnO₂ in the sample.

MnO₂ + C₂O₄ 2- + 4 H+ => Mn 2+ + 2 CO₂ + 2 H₂O

The rest of the oxalate will be titrated with permanganate

2 MnO₄- + 5 C₂O₄ 2- + 16 H+ => 2 Mn 2+ +10 CO₂ + 8 H₂O

The difference of the known amount minus titrated amount of oxalat gives the result.