Chemical Forums
Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: Marcool on January 10, 2021, 11:32:24 AM
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Hi
I'm having an issue trying to understand how to balance this redox reaction because I'm not entirely sure if the reaction makes sense in the first place.
The first thing I did was to balance the atoms on the left and on the right, but when i try to understand the oxidizing and reducing agent I get a bit confused.
Could you help me?
(https://i.ibb.co/DLmRhkS/8f3f8fd-3.png) (https://ibb.co/52CRmvf)
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What are your thoughts? Can you assign oxidation numbers to the atoms?
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Chlorine goes from +5 to +4 so it is reduced, and there's oxygen oxidizing from -2 to 0.
Is this correct?
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Yes
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Yes, that is correct. But this redox equation causes trouble.
It is easy to solve them by the algebraic method or by the method of oxidation degrees, but by making the electron balance from the right side of the equation to the left side (KClO3 + ... <== O2 + ClO2 + ...)
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Yes, that is correct. But this redox equation causes trouble.
It is easy to solve them by the algebraic method or by the method of oxidation degrees, but by making the electron balance from the right side of the equation to the left side (KClO3 + ... <== O2 + ClO2 + ...)
Would you be so kind to illustrate me better how to solve this? I'm getting confused..
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Just solve this equation
K2SO4 + O2 + ClO2 + H2O = KClO3 + H2SO4
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Just solve this equation
K2SO4 + O2 + ClO2 + H2O = KClO3 + H2SO4
Maybe I still have to study more cause I can't work out how to balance this equations. I get them all wrong. Thanks anyway
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O2 :larrow: 2ยท2e
Cl :rarrow: 1e
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I don't understand what you're trying to say... sorry but I'm really confused because I don't have something to write for the oxygen equation...
ClO3- + 2H+ + e- --> ClO2 + H2O
ClO3- + H2O --> 1/2 O2 + ClO3 + 2H+ +2e-
I then multiply times 2 the first equation but then I get confused...
The solution is meant to be
2KClO3 + H2SO4 --> K2SO4 + 1/2 O2 + 2ClO2 + H2O
So I could work this out even without doing any redox, just by balancing the masses...
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O2 + 4H+ + 4e- = 2H2O
ClO2 + H2O = ClO3- + 2H+ + e-
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Thanks a lot!
Now I think I got it.
I basically, in the end, after canceling out the same stuff on both sides of the reaction, was left with:
2 ClO3- + 2H+ --> 2ClO2 + 1/2 O2 +H2O
I returned to the molecular formulas and also understood that those two hydrogen atoms on the left were coming from the sulphuric acid. So I just converted 2H+ into H2SO4 and, clearly, added again K2SO4 on the right.
2 KClO3 + H2SO4 --> K2SO4 + 1/2 O2 + 2 ClO2 + H2O
Alternatively, if one doesn't like the half integers, they could just multiply everything times two.
Is this correct?
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4 KClO3 + 2 H2SO4 = 2 K2SO4 + O2 + 4 ClO2 + 2 H2O