A buffer is prepared by mixing 37.2 ml of 0.209 m naoh with 125.7 ml of 0.231 m acetic acid. what is the ph of this buffer? (the pka for acetic acid is 4.75.)

Respuesta :

Calculate the moles in each reactant

Acetic Acid (.231 mol/L)(0.125L)=  2.887 x 10^-2 mol AA

NAOH (.209mol/L)(.037L)= 7.733 x 10^-3 mol NaOH

As you can see, we have more AA and less NaOH, so NaOH is the limiting reactant.

NaOH + CH3COOH -> NaCH3COOH + H2O​

start: 4.5 mmol, 8.75mmol, 0, n/a

change: -4.5 mmol, -4.5mmol, 4.5mmol, n/a

after rxn: 0, 4.25 mmol, 4.5mmol, n/a​

Now your HH equation

pKa + log(conjugate base/acid) = 4.75 + log(4.5x10^-3 / 4.25x10^-3) =

pH = 4.76

What is Henderson-Hasselbalch equation?

The Henderson-Hasselbalch equation in chemistry and biology connects the pH of a weak acid solution to its acid dissociation constant, Ka, and the ratio of the concentrations of the acid and its conjugate base in equilibrium.

When both the pH of the solution and the ratio of ionized to unionized forms are known, the Henderson Hasselbalch equation can be used to calculate the pKa.

To learn more about Henderson Hasselbalch equation, refer to:

https://brainly.com/question/13423434

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