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Topic: Redox Question  (Read 2593 times)

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Offline Fablowable

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Redox Question
« on: October 09, 2016, 08:55:16 AM »
Hello folks,

this is my first post and I have a question about a redox reaction.

Citric acid reacts with Zinc ---> Zinc(II)citrate + Hydrogen

I have come this far but I am totally confused as to how to proceed.

                          h8c6o7 + Zn ---->Zn(h6c607) + H2

Oxidation numbers: 1/6/-2     0         +2 for Zn       0

Can you please tell me how to continue?

Thanks


Offline AWK

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Re: Redox Question
« Reply #1 on: October 09, 2016, 11:28:24 AM »
This is a single displacement reactionin which citrate3-, hydrogen citrate2- or dihydrogen citrate- (3 reaction are possible depending on stoichiometry) do not change oxidation state of any atom.
There is much better balancing this reaction:
H+ + Zn = Zn2+ + H2
 then adjusting coefficients of this reaction to stoichiometry of zinc reaction with citric acid.
AWK

Offline Fablowable

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Re: Redox Question
« Reply #2 on: October 09, 2016, 12:00:29 PM »
Thanks for the explanation!

This is the solution presented, however it just confuses me and I dont seem to understand how I can get there.


4 C3H4OH(COOH)3 + 6 Zn ⇄   2  Zn3(C3H4OH(COO)3)2  + 3 H2

Offline Borek

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Re: Redox Question
« Reply #3 on: October 09, 2016, 01:53:14 PM »
Thanks for the explanation!

This is the solution presented, however it just confuses me and I dont seem to understand how I can get there.


4 C3H4OH(COOH)3 + 6 Zn ⇄   2  Zn3(C3H4OH(COO)3)2  + 3 H2

C3H4OH(COOH)3 is just a complicated (although perfectly correct) way of presenting the citric acid. Would it be easier if I told you to write it as H3Citrate (which reflects the fact citric acid is triprotic)?
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Offline AWK

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Re: Redox Question
« Reply #4 on: October 09, 2016, 03:25:51 PM »
Quote
4 C3H4OH(COOH)3 + 6 Zn ⇄   2  Zn3(C3H4OH(COO)3)2  + 3 H2
Something wrong with coefficients (almost all)
AWK

Offline Vidya

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Re: Redox Question
« Reply #5 on: October 10, 2016, 10:37:33 PM »
only ionizable H will be reduced and one mole of citric acid has there moles of ionizable H which can give you 3/2 moles of H2
3H+ +3e ------> 3/2H2
It means
6H+ + 6e- -----> 3H2
Zn ----> Zn2+ + 2 e -
3Zn ----> Zn2+ + 6 e -

now you can add these reactions to get final equation
« Last Edit: October 11, 2016, 05:58:47 AM by Arkcon »

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