chem
posted by chem on .
Calculate the volume of 0.200 M acetic acid and the volume of 0.100 M sodium acetate required to make 200.0 mL of a buffer solution with pH = 5.00. The Ka for acetic acid at 298 K is 2.00 x 105.

Let x = mL acetate
Then 200x = mL acid

5.00 = 4.70 + log(0.1x)/[0.2(200x)]
in which mL x M = millimoles so
0.1x is mmoles acetate and
0.2x(200x) mmoles acid.
Solve for x = volume of base. I get 160 mL and 40 mL for the acid but check my work. 
Thank you

where does the 4.70 come from?

How did u solve for X

Sarah, 4.70 is what you get when you do the log (Ka)