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Topic: Correct Method for Acid/Base Standardization  (Read 3635 times)

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Offline Zen00

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Correct Method for Acid/Base Standardization
« on: August 10, 2017, 06:57:31 PM »
Should I titrate NaOH with KHP and HCl with Borax, or titrate NaOH with KHP then HCl with the NaOH?

The latter sounds like it would be introducing statistical error. Also is there a better standard to titrate the HCl with than Borax?

Offline Arkcon

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Re: Correct Method for Acid/Base Standardization
« Reply #1 on: August 11, 2017, 07:13:01 AM »
Should I titrate NaOH with KHP and HCl with Borax, or titrate NaOH with KHP then HCl with the NaOH?

Yes.

 ;D

Ok, sorry about that.  But I wanted to start off by letting you know that both are acceptable, and required, depending on what method is validated for the application involved.  We can't really help you more than that.

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The latter sounds like it would be introducing statistical error.
Yes you can insert multiple magnifying statistical errors.  Or you can do both perfectly (within experimental error) and get the best results.  That's why we validate.

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Also is there a better standard to titrate the HCl with than Borax?
The USP specifies tromethamine as the primary standard for volumetric HCl standardization.  It may be "better" or it may not be "better."  No one who uses standardized HCl to produce a pharmaceutical that will be sold in the United States is permitted to use anything else, unless they validate their new procedure.

A random blog on Google actually suggest using dried sodium carbonate as a standard.  WHich gives me a Yikes! moment, but whatevs: http://www.pharmaguideline.com/2010/09/preparation-and-standardization-of-1m.html

To what standard do you need your answer?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

Online Borek

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Re: Correct Method for Acid/Base Standardization
« Reply #2 on: August 11, 2017, 07:26:03 AM »
http://www.titrations.info/acid-base-titration-standard-substances (also sodium oxalate can be used, it is listed at http://www.titrations.info/potentiometric-titration-standard-substances).

These are just standard substances that are known to produce repeatable results, as Arkcon wrote, your specific application may require using a specific standard, not just one of these.
ChemBuddy chemical calculators - stoichiometry, pH, concentration, buffer preparation, titrations.info

Offline Zen00

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Re: Correct Method for Acid/Base Standardization
« Reply #3 on: August 11, 2017, 10:41:35 AM »
To what standard do you need your answer?

At our company we generally use the AOAC methods, which used the NaOH to standardize the HCl. I just wanted to make sure it's a correct method before moving on with it as I was concerned about the statistical errors that might crop in.

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