Question

buffers question: You need to prepare an acetate buffer of pH 6.21 from a 0.895 M acetic acid solution and a 2.96 M KOH solution. If you have 575 mL of the acetic acid solution, how many milliliters of the KOH solution do you need to add to make a buffer of pH 6.21? The pKa of acetic acid is 4.76.

Answer 1

pH = pKa + log[acetate/acetic acid]

acetic acid moles ---> (0.895*.575) = 0.514625
moles of acid reacted ---> x
therefore

6.21 = 4.76 + log[x/(x- 0.514625)]
solve for x, giving moles of base, then solve for volume

I hope i did this right, want to check before I waste a submission