A Mining Operation Needs to Separate Silver and Copper

A mining operation needs to separate silver and copper. You are hired as a summer intern in a beautiful Colorado mining town, and one of your tasks is to determine whether this separation can be accomplished by oxidizing the metals to Ag⁺ and Cu⁺, each one at a concentration of 0.15 M, and then precipitating one as the chloride salt without precipitating the other. AgCl precipitates first. What is the concentration of the Ag⁺ remaining in solution when CuCl begins to precipitate? For AgCl, pK_sp = 9.74, and for CuCl, pK_sp = 6.76.

A) 1.57 *10^-2 M
B) 1.57 *10^-4 M
C) 2.23 *10^-2 M
D) 2.23 * 10^-4 M
E) 3.72 * 10^-3 M