I am planning an experiment where I am measuring the buffer capacity of a mixture. However the mixture has two weak acids in it. Will having multiple weak acids in the mixture cause any changes in the procedure? I
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$\begingroup$ Calculate or measure? Measuring is the same, calculation is more complicated. $\endgroup$– PoutnikCommented Jun 5 at 4:31
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$\begingroup$ Yes it will make the system more complex to solve but not impossible, what is your acid? $\endgroup$– jlandercyCommented Jun 5 at 6:27
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$\begingroup$ @Poutnik I think its measuring? My aim is to titrate against a base to see how much is needed to change the pH of the mixture/solution though $\endgroup$– user146630Commented Jun 5 at 8:04
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$\begingroup$ @jlandercy it is an exfoliating serum so it has equal concentrations of glycolic acid and lactic acid in the serum $\endgroup$– user146630Commented Jun 5 at 8:05
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1 Answer
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Measuring of pH buffer capacity does not care about the particular buffer composition. It just registers pH changes after addition of a strong base or acid.
The capacity can be expressed
- absolutely ( in amount of acid/base )
- relatively (in formally provided concentration of the strong acid/base before it neutralizes the buffer counterpart.
Note also there is
the differential buffer capacity
- absolute $\dfrac{\text{d}n}{\text{d(pH)}}$
- relative $\dfrac{\text{d}c}{\text{d(pH)}}$
the integral buffer capacity
- absolute $\Delta n$ for $\Delta \text{pH}=1$
- relative $\Delta c$ for $\Delta \text{pH}=1$
For more, you may want to review search results for
site:stackexchange.com OR site:libretexts.org OR site:wikipedia.org "pH buffer" capacity
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$\begingroup$ Thank you so much for clearing it up for me! $\endgroup$ Commented Jun 6 at 20:33