Question

What is the pH of a 40.0 40.0 mL solution that is 0.11 0.11 M in CN − CN− and 0.21 0.21 M in HCN HCN ? The K a Ka for HCN is 4.9 × 10 − 9

Answer 1

pH=8.03

Step-by-step explanation:

From the Henderson-Hasselbalch equation:

we know that

pH = pKa + log (base / acid)

plugging the values from the question we can write

pH = 8.31 + log (0.11 / 0.21)

pH = 8.31-0.280

pH=8.03