You have 475 mL of an 0.47 M acetic acid solution. What volume (V) of 1.10 M NaOH solution must you add in order to prepare an acetate buffer of pH = 5.00?
475 mL x 0.47 = 223 mmols HAc
.........HAc + OH^- ==> Ac^- + H2O
initial..223....0........0.......0
add.............x................
change...-x....-x........x.......x
equil...223-x....0.......x........x
Substitute the equil line into the Henderson-Hasselbalch equation and solve for x = millimols OH^- to be added.
Then M = mmols/mL or mL = mmols/M and solve for mL.