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Topic: Determination of citric acid concentration  (Read 1883 times)

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Offline Referendum

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Determination of citric acid concentration
« on: October 24, 2015, 10:53:28 PM »
The beverage club soda contains potassium citrate, according to the label.
Using standardized solutions, I believe I know how to titrate a sample and solve the concentration of citric acid in a sample.
However, I'm hung up on this question. How do I relate the moles of acid to moles of salt?

Let's say potassium citrate is formed by:
1 C6H8O7 + 3 KOH  :rarrow: 1 C6H5K3O7 + 3 H2O

Am I crazy? Am I overlooking something glaringly obvious, or is the mol:mol ratio of the salt and acid 1:1, and thus I can treat the concentration of acid as that of the salt?
 
Any guidance would be appreciated. I'm under the weather and going crazy right now.

Offline Borek

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Re: Determination of citric acid concentration
« Reply #1 on: October 25, 2015, 04:57:56 AM »
Yes, it is 1:1 in the neutralization reaction.

However, it is not clear what you are trying to do. The beverage can contain both the citrate and the citric acid, so if you will titrate just the acid, you won't know what was the total amount of the citrate in all forms. Plus, you can't determine amount of citrate salt titrating it as if it was an acid.
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Offline Referendum

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Re: Determination of citric acid concentration
« Reply #2 on: October 25, 2015, 01:13:18 PM »
Thank you. I was in a bad state of mind yesterday, and for some reason thought I could count the amount of potassium citrate as citric acid. I just had to ask in a way that didn't make me seem like an idiot...even though that's really the case.

Thanks again.

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