Acid and bases question (1 Viewer)

[mathsfreak1010]

What volumes of 0.2M HCOOH and 2M NaOH would make 500ml of a buffer with the pH as the one made from 475ml of 0.2M benzoic acid and 25ml of 2M NaOH.
Ka(HCOOH)= 1.8x10^-4
Ka (Benzoic Acid)= 6.3x10^-5


the answer is 0.121L of 2M NaOH and 0.379L of 0.2M HCOOH


Thanks