Question

What is the equilibrium Ag⁺ concentration when 2.13 L of a 0.111 M silver fluoride solution are mixed with 2.05 L of a 0.112 M ammonium sulfide solution?

[Ag⁺] = M

Answer 1

concentration of AgF = 2.13 x 0.111 / 2.13 + 2.05

                                 = 0.05656 M

concentration of (NH4)2S = 2.05 x 0.112 / 2.13 + 2.05

                                       = 0.05493 M

2 Ag+ +       S2-    ----------> Ag2S +    2 NH4F

2 1

0.05656     0.05493

here Ag+ is limiting reagent.

[S2-] = 0.05492 - (0.05656 / 2) = 0.02665 M

Ksp = [Ag+]^2[S2-]

1.0 x 10^-49 = [Ag+]^2 x 0.02665

[Ag+] = 1.94 x 10^-24 M