Question

Question 1 Part A:

Solid potassium sulfide is slowly added to 50.0 mL of a 0.216 M copper(II) iodide solution until the concentration of sulfide ion is 0.0510M. The percent of copper(II) ion remaining in solution is ? %.

Question 1 Part B:

Solid potassium sulfide is slowly added to 75.0 mL of a nickel(II) bromide solution until the concentration of sulfide ion is 0.0432 M. The maximum amount of nickel ion remaining in solution is ? M.

Answer 1

1)

Part A)

CuS   --------------> Cu2+   +    S2-

Ksp = [Cu2+][ S2-]

7.9 × 10^-37 = [Cu2+] [0.0510]

[Cu2+] = 1.549 x 10^-35 M

% Cu2+ ion = (1.549 x 10^-35 / 0.216 ) x 100

                   = 7.17 x 10^-33 %

Part B)

NiS -----------> Ni2+   +   S2-

Ksp = [Ni2+][S2-]

3.0 x 10^-21 = [Ni2+] [0.0432]

[Ni2+] = 6.94 x 10^-20 M

note : in part B . you missed the concentration of nickel(II) bromide