Equation for the oxidation reaction for KMnO4 solution

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Discussion Overview

The discussion revolves around the oxidation reactions involving KMnO4 solutions, particularly in the presence of dilute HCl and other compounds. Participants explore half-equations, oxidation states, and the balancing of redox reactions, addressing both theoretical and practical aspects of these chemical processes.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant questions what is being oxidized in the reaction involving KMnO4 and dilute HCl.
  • Another participant suggests that chlorides are oxidized, prompting further inquiry into the oxidation states of chlorine.
  • There is a discussion about the oxidation half-equation for chloride ions, with some proposing Cl- to Cl2 as the product.
  • Participants debate the reduction half-equation for permanganate, with one stating it involves MnO4- and hydrogen ions.
  • Concerns are raised about balancing the overall reaction, with suggestions to adjust coefficients to ensure electron cancellation.
  • In a later part of the discussion, participants explore the oxidation states of sulfur in Na2SO3, with some asserting that sulfur is oxidized to a +6 state.
  • There is confusion regarding the oxidation states and the role of spectator ions in the reactions discussed.
  • Participants also discuss the oxidation of hydrogen peroxide in a reaction with KMnO4, with differing views on the products formed.
  • One participant mentions the potential oxidation of Mn2+ to MnO4- and questions the half-equation for this process.

Areas of Agreement / Disagreement

Participants express various viewpoints on the oxidation processes and the corresponding half-equations, indicating that multiple competing views remain. The discussion does not reach a consensus on several points, particularly regarding oxidation states and the roles of different species in the reactions.

Contextual Notes

Participants highlight the importance of balancing half-reactions and the potential complexity of oxidation states, noting that some assumptions about oxidation states may not apply universally. There is also mention of the need for clarity in defining the roles of ions in the reactions.

  • #31


Ok so I get: 2MnO4- + 16H+ + 5S+4 ---> 2Mn2+ + 4H2O + 5S+6
 
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  • #32


No, you can't remove single atom from the complex ion and use it to balance balance reaction. You start with SO32- and you end with SO42-.

agrocadabra said:
Why is it +6, why not something else, something higher?

Because these are properties of sulfuur, properties that you can check looking at the periodic table.

I'm using ON numbers because I don't know how else to go about it.

I gave you a link to a page where half reactions are explained.

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methods
 
  • #33


Ok so the third is KMnSO4 solution mixed with dilute H2O2 in the presence of dilute H2SO4:

now the H2O2 is the reductant right.. so we have H+ ---> Hn+ + n electrons.. how do we know what it is oxidised to?
 
  • #34


You start with SO32- and you end with SO42-. How are there electrons then to cancel out the 5 from the MnSO4?
 
  • #35


KMnSO4? No such animal.

Strange as it sounds, hydogen peroxide is oxidised to oxygen.

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  • #36


2MnO(4-) + 16H(+) + 5SO3(2-) + 50(2-) ---> 5SO4(2-) + Mn(2+) + 4H2O ?
 
  • #38


agrocadabra said:
50(2-)

Where did you got it from?

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  • #39


ok so mix diluted hadfield solution (steel dissolved in
nitric acid followed by treatment with ammonium
peroxydisulfate to oxidize carbon and treated with Sn(2+)
to reduce the Fe(3+) to Fe(2+) ) in a conical flask with
some H2SO4 and some KIO4.. the whole idea is to find out
the amount of manganese in the steel.. What is the
oxidation half equation that converts Mn(2+) to MnO4(-)?
 
  • #40


I thought Mn(2+) + IO4(-) ---> MnO4- + I- ?
 
  • #41


Strange, as far as I know Mn2+ can be oxidized to permanganate by ammonium peroxydisulfate in the presence of catalytic amounts of Ag+; no need for further Fe and oxidation by periodate.

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Last edited:
  • #42


well my notes seem to indicate IO4 has something to do with the oxidation..
 
  • #43


It is a strong oxidizer, but I don't see a point in using it here. Perhaps you have not shown complete procedure.

--
methods
 

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