Question

Uric acid can collect in joints, giving rise to a medical condition known as gout. If the pKa of uric acid is 3.89, what is the pH of a 0.0140 M solution of uric acid?

Answer 1

Answer:

pH = 2.87

Explanation:

Let us represent uric acid as HA

The dissociation will be:

                     $HA ---> H^{+} + A^{-}$

Let "x" concentration of HA dissociates so it will give x concentration of hydrogen ion and the conjugate base.

$Ka=\frac{[H^{+}][A^{-}]}{[HA]}$

pKa = 3.89

Therefore Ka = 0.000129

Putting values

$0.000129 = \frac{x^{2} }{(0.014-x)}$

on may ignore x in denominator

x = 0.00134 M

[H⁺] = 0.00134

pH = -log[H⁺] = 2.87