Calculate the pH of a solution containing 0.0360M glutaric acid and 0.020M potassium hydrogen glutrate.

Question

The Ka values for glutaric acid are 4.52*10^-5 and 3.78*10^-6

Answer 1

This is an acidic buffer, therefore, as per Henderson- Hasselbalch equation, the pH of the buffer is:

pH = pKa1 + log [conjugate base] / [acid]

pKa1 = - log Ka1 = - log 4.52 x 10^-5 = 4.345

Therefore, pH = 4.345 + log (0.020 / 0.0360) = 4.09