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Topic: Table for pH values of equivalence points  (Read 1990 times)

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Offline pcm81

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Table for pH values of equivalence points
« on: June 27, 2018, 09:06:59 PM »
My google-fu is failing me right now... I am looking for a table of pH values of equivalence points between acids and bases. Specifically interested in NaOH vs Oxalic acid and NaOH vs phosphoric acid, but a large table for many combinations would be the best.

Basically, i am doing titrations using a pH meter and when i plot the data i interpolate to the steepest slope in attempt to get the value of titrate that would give me the equivalence point. Naturally i can calculate pH at that value from the same interpolation. My goal here is to use a documented pH for the equivalence point to check my interpolation. Or in some cases interpolate to that pH value rather than just take mid point between 2 neighbouring points.

Thanks ahead

Offline Borek

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Re: Table for pH values of equivalence points
« Reply #1 on: June 28, 2018, 03:48:52 AM »
That's not how it works. Look for table of pKa values and use them to calculate equivalence points.

http://www.titrations.info/acid-base-titration-equivalence-point-calculation

http://www.chembuddy.com/?left=pH-calculation&right=pH-salt-solution
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Offline pcm81

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Re: Table for pH values of equivalence points
« Reply #2 on: June 28, 2018, 05:42:49 PM »
That's not how it works. Look for table of pKa values and use them to calculate equivalence points.

http://www.titrations.info/acid-base-titration-equivalence-point-calculation

http://www.chembuddy.com/?left=pH-calculation&right=pH-salt-solution

Thanks. Figured it out... Been waaaay too long since the last time i used my brain. Really, i should be smarter than to have asked this question, since i never specified the reaction volume... And pH would depend on that via concentration...

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