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Topic: redox balancing: FeS2+ Na2O2 ---> ..  (Read 739 times)

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Offline xshadow

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redox balancing: FeS2+ Na2O2 ---> ..
« on: June 19, 2021, 11:35:37 AM »
HII!!

Have to balance this redox:

FeS2 + Na2O2  -->  Na2SO4 + Na2O + Na2FeO4

First I balanced the Sulfur atom:
FeS2 + Na2O2  --> 2 Na2SO4 + Na2O + Na2FeO4
FeS2 + Na2O2  --> 2 Na2SO4 + Na2O + Na2FeO4

OX1:  2S (-1)  ---> 2S (VII)  + 14 e-
OX2:  Fe(II) ---> Fe (VI) + 4 e-

OX TOT: 18e-

Now I have trouble with the oxygen/ reduction
Because on the left I have  Na2O2 with N.O = -1.
On the right I have three oxygen with  N.O= -3 and I don't know how to advance.

If I consider only Na2O on the right  I get:
FeS2 + Na2O2  --> 2 Na2SO4 + 2Na2O + Na2FeO4    (balanced the oxygen involved in the redox as i done before with Sulfur)

2O (-1) + 2e- --> 2O (-2)

OX TOT : 18 e-   X1
RID: 2 e-           X9


FeS2 + 9Na2O2  --> 2 Na2SO4 + 18Na2O + Na2FeO4

But doens't work.
Thanks

Offline Borek

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Re: redox balancing: FeS2+ Na2O2 ---> ..
« Reply #1 on: June 19, 2021, 12:45:53 PM »
OX1:  2S (-1)  ---> 2S (VII)  + 14 e-

S(VI), but I suppose that's just a typo, as electrons are OK.

Quote
On the right I have three oxygen with  N.O= -3

Another typo?

If I consider only Na2O on the right  I get:
FeS2 + Na2O2  --> 2 Na2SO4 + 2Na2O + Na2FeO4  (balanced the oxygen involved in the redox as i done before with Sulfur)

Not sure what you did here nor why. Oxygen is not balanced.

This is actually easier to balance just by inspection, start with a single FeS2 and see where it leads you.
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