A chemist prepares a saturated solution of solid AgCl in distilled water at 25 °C and then slowly adds solid NaCl until its concentration in the beaker reaches 0.020 M.
Ksp(AgCl, 25 °C)=1.8×10−10
Assume that no other reactions occur and that temperature is constant.
(a) Write the balanced dissolution equilibrium for AgCl(s) in water and the corresponding Ksp expression.
(b) Using principles of chemical equilibrium, describe qualitatively why the addition of NaCl decreases the molar solubility of AgCl.
(c) Derive an algebraic expression for the new molar solubility s′ of AgCl when the concentration of chloride ion in solution is fixed at [Cl−]added. Simplify your result to show s′=[Cl−]addedKsp under the assumption that [Cl−]added≫s′.