Question

what volume of 2.00mol/L NaOH must be added to 100.00mL of 2.50mol/L HCOOH to prepare a buffer with pH=4.00?

Answer 1

D:

Answer 2

You need to look up the pKa of formic acid, it should be in the back of your chemistry book or on the internet. Remember that NaOH (lye) is a strong base, and so it will disassociate completely in solution meaning it for every mole of NaOH you will turn one mole of HCOOH into HCOO-.

Answer 3

Also, you could just fill a beaker with HCOOH and then put a pH meter in there and then add NaOH until it becomes the pH you want and not waste time on a stupid calculation. That's what chemists actually do, unless for some reason it's a valuable substance.

Answer 4

^_^Thanks a lot Kainui :D