Chapter 17 Principles of Chemical Reactivity: Other Aspects of Aqueous Equilibria - Study Questions - Page 677c: 59

See the answer below.

Pure water: $Ksp=[Ag^+][I^-]=s^2$ $s=\sqrt{8.5\dot{}10^{-17}}=9.22\dot{}10^{-9}\ M$ $s^*=9.22\dot{}10^{-9}\ mol/L\dot{}234.77\ g/mol=2.16\dot{}10^{-6}\ mg/mL$ With AgNO3: $Ksp=s\dot{}(s+0.020)$ $s=4.25\dot{}10^{-15}\ M$ $s^*=4.25\dot{}10^{-15}\ mol/L\dot{}234.77\ g/mol=9.98\dot{}10^{-13}\ mg/mL$