Question

The ionization constant of benzoic acid is 6.46 × 10^–5 and Ksp for silver benzoate is 2.5 × 10^–13. How many times is silver benzoate more soluble in a buffer of pH 3.19 compared to its solubility in pure water?

Answer 1

Since pH = 3.19, 

Let the solubility of C₆H₅COOAg be x mol/L. 

Then, 

Thus, the solubility of silver benzoate in a pH 3.19 solution is 1.66 × 10^–6 mol/L. Now, let the solubility of C₆H₅COOAg be x’ mol/L. 

Hence, C₆H₅COOAg is approximately 3.317 times more soluble in a low pH solution.