Applications of Aqueous Equilibrium (Show work and Answer)

Question

Calculate the pH of a buffer system made up of 0.15 M HNO₂ and 0.35 M NaNO₂

K_a = 4.5 E^-4

Answer 1

Buffers:

Use of Henderson Hasselbalch equation...

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

pKa = -log 4.5x10^-4 = 3.35

pH = 3.35 + log (0.35/0.15) = 3.35 + 0.368

pH = 3.72