Question

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 10-5.

Answer 1

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

Answer 2

Thank you

Answer 3

where does the 4.70 come from?

Answer 4

How did u solve for X

Answer 5

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