You need to produce a buffer solution that has a pH of 5. You already have a solution that contains 10 \rm mmol (millimoles) of acetic acid.

You need to produce a buffer solution that has a pH of 5.06. You already have a solution that contains 10 rm mmol (millimoles) of acetic acid. How many millimoles of acetate (the conjugate base of acetic acid) will you need to add to this solution? The pKa of acetic acid is 4.74.