Answer :
By using the Henderson-Hasselbalch equation, we can calculate that the concentration of acetic acid in the given buffer is 57.5 mM.
When calculating the pH value of a buffer system, we use the Henderson-Hasselbalch equation:
[tex]pH = pK_{a} + log\frac{[base]}{[acid]}[/tex]
pKa - the negative logarithm of the acidic constant (for acetic acid, pKa = 4.76)
[base] - concentration of the basic (sodium acetate) component
[acid] - concentration of the acidic (acetic acid, AcOH) component
If we plug the known values (pH = 5; [base] = 100 mM; pKa = 4.76) in the equation we get:
[tex]5 = 4.76 + log\frac{100 mM}{[AcOH]}[/tex]
[tex]log\frac{100 mM}{[AcOH]} = 5-4.76[/tex]
[tex]log\frac{100 mM}{[AcOH]} = 0.24[/tex]
[tex]\frac{100 mM}{[AcOH]}= 10^{0.24}[/tex]
[tex]\frac{100 mM}{[AcOH]}= 1.74[/tex]
[AcOH] = 100 mM / 1.74
[AcOH] = 57.5 mM
You can learn more about buffers here:
brainly.com/question/22821585
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