Find the mass of sodium formate that must be dissolved in 200.00cm^3 of a 1.0M solution of formic acid to prepare a buffer solution with pH=3.40? I have no clue how to work this out. Please help me.

Answer 1

If you know how to use the Henderson-Hasselbalch equation that is the way to go. If not, let me know and it can be done another way.

Answer 2

Is it something like PH=pKa +log [base]/[acid]

3.40=??
How do I find the pKa?