How to find the volume of 0.20 M NaOH required to adjust the pH of the 0.10 M acetic acid solution to a pka value of acetic acid. I have 50 ml of acetic acid. pka = 4.76. I'm really stuck on this question and don't know how to do it. I get to a certain part and I get stuck. Please help!

Question

anonymous · Answer

@abb0t please help

cuanchi · Answer

this is a titration of a weak acid with a strong base. At the pKa, the system is a buffer system, where you have the acetic acid, and the salt at the same concentration. This point of titration is the half volume of the equivalent point.
It that helps?

anonymous · Answer

umm i know how it works...but i just get stuck with the calculation

gebooors · Answer

When a half of the amount of substance of asetic  acid is 
Netralized, pH = pKa.  n = cV = 0.10 M x 0.050 l = 0.005 mol.
You need 0.0025 mol NaOH.  V = n/c, in litres.