General Chemistry 2

Question

What is the pH of a solution of 0.300 M HNO₂ containing 0.250 M NaNO₂? (Ka of HNO₂ is 4.5 × 10⁻⁴)

Answer 1

pKa = -log Ka = -log 4.5x10^-4 = 3.35

Henderson Hasselbalch equation:

pH = pKa + log [conj.base]/[acid]

pH = 3.35 + log (0.250/0.300)

pH = 3.35 + log 0.833 = 3.35 -0.0792

pH = 3.271