What is the pH of a .20M HA solution (Ka=1.0x10^-6) that contains a 0.40M NaA?

Answer 1

I found that it came to 6.30 for the pH. So I first balanced the equation set up an "ICE" box and then solved for x using the Ka equation...Ka=([H+][A-])/([HA]), I neglected the +x and -X and plugged in to solve. Then I got the pH by doing the negative log of the x. Hope this helped :)

Answer 2

I agree with 6.30 but I used the Henderson-Hasselbalch equation. It's easier and you don't need an ICE chart.