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Topic: question about hydrogen peroxide being used as an oxidant.  (Read 3568 times)

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Offline brycebb

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question about hydrogen peroxide being used as an oxidant.
« on: July 26, 2012, 01:27:24 AM »
What exactly happens when the hydrogen peroxide is added in this reaction for making iodine?  Now I tried making the chemical equations for the process and this is what I came up with.

KI +HCl---> HI + KCl

Now for when the hydrogen peroxide is added I get this
HI+H[2]0[2]--->
I can't seem to figure out the products.  Now this should be a simple question but I'm still learning about the elementary aspects of chemistry, so if anyone can help me out and maybe tell me how the hydrogen peroxide acts as the oxidant and what products can be formed.  Also, not related to this question, why is it that the oxygen only has a charge of -1 in the hydrogen peroxide molecule?

Offline Dan

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Re: question about hydrogen peroxide being used as an oxidant.
« Reply #1 on: July 26, 2012, 03:08:21 AM »
I can't seem to figure out the products.

Well, you know one of them is iodine, right?

Consider the redox balance. What is being oxidised? If something is oxidised, something else must be reduced...

Quote
Also, not related to this question, why is it that the oxygen only has a charge of -1 in the hydrogen peroxide molecule?

H2O2 has no charge, it is a neutral molecule.

Are you referring to the oxidation state of O in H2O2 (which is -1)?
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Offline AlphaScent

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Re: question about hydrogen peroxide being used as an oxidant.
« Reply #2 on: July 26, 2012, 09:59:27 AM »
How does the HCl + KI  :rarrow: HI + KCl matter to this question? 

So, Dan specified that the oxygen atom has a oxidation state of -1 in hydrogen peroxide.  If it were to react with the iodide, what oxidation state would you expect it to be in? 

elephant toothpaste is not minty fresh either : )  :larrow: not realted, just a joke about this reaction
If you're not part of the solution, then you're part of the precipitate

Offline brycebb

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Re: question about hydrogen peroxide being used as an oxidant.
« Reply #3 on: July 26, 2012, 12:43:25 PM »
I can't seem to figure out the products.

Well, you know one of them is iodine, right?

Consider the redox balance. What is being oxidised? If something is oxidised, something else must be reduced...

Quote
Also, not related to this question, why is it that the oxygen only has a charge of -1 in the hydrogen peroxide molecule?

H2O2 has no charge, it is a neutral molecule.

Are you referring to the oxidation state of O in H2O2 (which is -1)?
when it comes to the hydrogen peroxide question, yes i am referring to the oxidation state of the oxygen within the molecule being -1.  Normally it is -2, such as with water and carbon dioxide, I was just curious as to why in hydrogen peroxide it was different.  And I figured that the Iodine is produced along with water, would that be correct?

Offline Dan

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Re: question about hydrogen peroxide being used as an oxidant.
« Reply #4 on: July 26, 2012, 01:16:07 PM »
Yes. Iodide (ox. state -1) is oxidised to iodine (ox. state 0), and hydrogen peroxide (ox. state -1) is reduced to water (ox. state -2).
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Offline brycebb

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Re: question about hydrogen peroxide being used as an oxidant.
« Reply #5 on: July 27, 2012, 12:26:43 AM »
Yes. Iodide (ox. state -1) is oxidised to iodine (ox. state 0), and hydrogen peroxide (ox. state -1) is reduced to water (ox. state -2).
thanks, and again I apologize if these questions seem really elementary, I just started studying chemistry

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