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Use of a buffer such as Sodium Acetate in Example 9

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dlparkhurst:
I think your solution definition is wrong. The pH of a NaAc solution is not 4.88, which is what you specified.  The calculation I attached used pH to charge balance the solution and found a pH of 8.4. So here is one way to do the calculation using charge balance:


--- Code: ---SOLUTION 1       0.01 molal NaAcetate   
        pH      4.68   charge           
        pe      4.0   
        temp    25                     
        units   mol/kgw                 
        Ac      0.01     
        Na      0.01

REACTION 1
HAc 1
10 mmol
END
[/code

Alternatively, you can add both NaAc and HAc in REACTION:

[code]
SOLUTION 1     
pH 7
REACTION 1
HAc  1
NaAc 1
10 mmol
END

--- End code ---

If you want to use your measured pH, you can do this (which will include a small charge imbalance in the calculation):


--- Code: ---SOLUTION 2       0.01 molal NaAcetate   + HAcetate
        pH      4.68   
        pe      4.0   
        temp    25                     
        units   mol/kgw                 
        Ac      0.02     
        Na      0.01

--- End code ---

brunagr:
Hello Mr. Parkhurst,

Thank you very much for your attention and help, I appreciate it! That was very helpful!

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