You have 875 mL of an 0.53 M acetic acid solution. What volume (V) of 1.30 M NaOH solution must you add in order to prepare an acetate buffer of pH = 4.94? (The pKa of acetic acid is 4.76.)
Use the HH equation.
Acetic acid = HAc
millimols HAc = M x mL = about 460 but you need to do it more accurately.
......HAc + NaOH ==> NaAc + H2O
I.....460.....0.......0.......0
add...........x..............
C.....-x......-x......x.
E....460-x.....0.......x
Then 4.94 = 4.76 + log(x)/(460-x)
Solve for x = millimols NaOH and convert to mL