How to Balance Redox Reactions in Aqueous Solution

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Discussion Overview

The discussion revolves around balancing a redox reaction in an aqueous solution, specifically the reaction between HIO3, FeI2, and HCl to produce FeCl3, ICl, and water. Participants explore various methods for balancing the equation, including the use of half-reactions.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant outlines the oxidation states of the reactants and products but expresses uncertainty about how to balance the chlorine and iodine in the reaction.
  • Another participant suggests balancing iodine and chlorine first, followed by oxygen and hydrogen, as a method to approach the problem.
  • There is confusion about the order of balancing and whether to balance the original equation or use half-reactions directly.
  • A participant proposes that balancing the original equation might be time-consuming and questions the necessity of that approach when half-reactions could be used instead.
  • One participant mentions that there are multiple species being oxidized and reduced simultaneously, suggesting an algebraic approach to balancing the equation.
  • Another participant notes that while the method was not enforced, they feel the teacher expects the use of half-reactions based on prior instruction.

Areas of Agreement / Disagreement

Participants express differing opinions on the best method to balance the redox reaction, with no consensus on whether to prioritize balancing the original equation or using half-reactions. Some participants believe that balancing the original equation is necessary, while others advocate for the use of half-reactions as a potentially quicker method.

Contextual Notes

Participants have not resolved the specific steps for balancing the reaction, and there are uncertainties regarding the application of half-reactions versus balancing the overall equation. The discussion reflects varying levels of familiarity with redox balancing techniques.

downwithsocks
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Homework Statement



HIO3 + FeI2 + HCl ==> FeCl3 + ICl + HOH


Homework Equations


Directions say it's in an aqueous solution, and HCl is a reactant, so you can add H2O and H+ to balance, right?


The Attempt at a Solution


I first found all the oxidation states:
HIO3
H = +1
I = +5
O = -2

FeI2
Fe = +2
I = -1

HCl
H = +1
Cl = -1

FeCl3
Fe = +3 (oxidation)
Cl = -1

ICl
I = +1 (reduction)
Cl = -1

HOH
H = +1
O = -2

Then tried writing/balancing the half reactions.

FeI2 ==> FeCl3 + e-

But I'm kind of stuck here, can I use HCl to balance? How else do I balance that Cl? And what about the I?
 
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Do you have to balance the equation given or something else (net ionic equation, half-reaction)?

To balance the equation you gave, first balance iodine and chlorine, then oxygen and then hydrogen, then keep going. That should help get you started.
 
I have to balance the equation given, but obviously using half reactions and such since it's a redox equation.

I'm not sure exactly what you mean by "first balance iodine and chlorine".
If I have "FeI2 ==> FeCl3 + e-" as part of one half-reaction, how exactly do I balance the iodine and chlorine? Since ICl is a product, can I use that to help balance?
ie, FeI2 ==> FeCl3 + e- + 2ICl
? And then from there how would I balance the Cl?
 
downwithsocks said:
I have to balance the equation given, but obviously using half reactions and such since it's a redox equation.

I'm not sure exactly what you mean by "first balance iodine and chlorine".

I meant in the original chemical equation.
 
So I have to balance the original equation before trying to balance it the redox way? That seems like it would take forever, I thought that was the point of the half-reactions and such :p
 
I think it can be done in 10-15 minutes that way, if you don't make a mistake.

Half-reactions or some other way might be easier or faster, but I've never worked with them.
 
This one is tricky, there are two things being oxidized and two being reduced at the same time. I would go for algebraic approach (of balancing chemical equations). If you were told to balance, but method was not enforced, you should select the one that gets job done. Doesn't matter which one it is.


--
 
Well, we weren't specifically told how, but it's practicing balancing redox equations and that's the way we were taught, so I assume that's the way the teacher wants it done. I'll check out your link though, thanks.
 

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