Question

If a buffer solution is 0.270 M in a weak acid (Ka = 9.0 × 10-5) and 0.550 M in its conjugate base, what is the pH?

Answer 1

We can use the Henderson-Hasselbalch equation here:\[pH=pKa+\log(\frac{[A^-]}{[HA]})\]Go ahead and try it from there. You're given three of the four variables expressed above.

Answer 2

Alright, then:\[pH=4.05+\log(\frac{0.550}{0.270})=4.35\]