Answer:
pH = 6.167
Explanation:
The weak acid, HX, reacts with NaOH as follows:
HX + NaOH → NaX + H₂O
Where 1 mole of HX with 1 mole of NaOH produce 1 mole of NaX (The conjugate base of the weak acid).
Now, using H-H equation:
pH = pKa + log [NaX] / [HX]
Where pH is the pH of the buffer
pKa is -log Ka = 6.167
And [NaX] [HX] are the molar concentrations of each specie
Now, at the neutralization of the half of HX, the other half is as NaX, that means:
[NaX] = [HX]
And:
pH = pKa + log [NaX] / [HX]
pH = 6.167 + log 1
pH = 6.167
