posted by emily .
Hi, i'm really desperate! could anyone please help me with this question, I'm stumped.
'A buffer is prepared by mixing a 100.omL of a 0.100 M NH3 solution with a 0.200M solution of NH4CL solution and making the total volume up to 1.000L of water. What is the volume of NH4Cl solution required to achieve a buffer at ph=9.5? Ka of NH4=5.6x10^-10. The textbook says the answer is 28.1mL.