posted by Anonymous .
You have to prepare a pH 3.50 buffer and you have .10M HCOOH and .10M HCOONa, how many milliliters of each solution do you neeed for 1 liter of buffer
Use the Henderson-Hasselbalch equation.
You will need to look up Ka for formic acid and convert to pKa.
Calculate the ratio Base/acid.
Then acid + base = 1
and base/acid = from above.
Two equations and two unknowns. Solve for acid and base. I get something like 600 mL acid and 400 mL base but those are just close numbers.