Acetic acid (CH3COOH) has a Ka of 1.8x10^-5. a buffer is to be prepared with a pH of 5.00 from solutions of CH3COOH and sodium acetate (NaCH3COO) of the same concentration. How many mLs of NaCH3COO would have been added to 100 mL of CH3COOH to make the proper buffer solution??

Answer 1

Use the Henderson-Hasselbalch equation.
5.00 = 4.76 (or whatever you have for pKa) + log(base)/(acid)
Solve for B/A.
You don't have a molarity of either given BUT you can make it easy and assign 1.0M to each.
I did a quickie calculation and came up with about 174 mL but you should confirm that and do it more accurately.