Question

Consider the dissolution of the slightly soluble salt silver hypochlorite (AgClO) with a Ksp value of 5.7 x 10-12 .

1. Calculate the mass (in grams) that dissolves in 1.00 L of deionized water. (5 pts)

2. Calculate the mass (in grams) that dissolves in 1.00 L of an aqueous solution buffered at pH = 2.15. (10 pts)

3. Calculate the mass (in grams) that dissolves in 1.00 L 0.200 M Na2S2O3 solution (10 pts)

Answer 1

1. AgClO (aq) Ag⁺ (aq) + ClO^- (aq)

K_sp = [Ag⁺][ClO^-] = [C]²

[C] = 5.7 x 10^-12 = 2.38 x 10^-6 mole/L = 2.38 x10-6 x 159.32 g/L = 0.000379 g/L

b) Aqueous AgClO is basic in nature. So at lower pH, solubility of AgClO will increase according to Le-Chatelier's principle.

c) Ag⁺ (aq) + 2S₂O₃^2- (aq) [Ag(S₂O₃)₂]^3- (aq)

So for each mole of Ag⁺ one requires 2 moles of S₂O₃^2-

1 L of 0.2 M S₂O₃^2- = 0.2 mole

so moles of Ag⁺ must be = 0.2/2 = 0.1 mole = 0.1x112 g = 11.2 g of Ag