In: Chemistry
Given the two reactions PbCl2⇌Pb2++2Cl−, K3 = 1.85×10−10, and AgCl⇌Ag++Cl−, K4 = 1.13×10−4, what is the equilibrium constant Kfinal for the following reaction? PbCl2+2Ag+⇌2AgCl+Pb2+
PbCl2(s)⇌Pb2+(aq)+2Cl−(aq), K3 = 1.85×10−10
k3 =
[Pb^+2][Cl-]^2/[pbcl2]
AgCl(s)⇌Ag+(aq)+Cl−(aq) K4 = 1.13×10−4
k4 = [Ag^+][Cl]/[AgCl]
K4^2 =
[Ag^+]^2[Cl]^2/[AgCl]^2
PbCl2+2Ag+⇌2AgCl+Pb2+
k5 =
[AgCl]^2[pb^+2]/[pbcl2][Ag^+]^2
K5 =
K3/K4^2
=
[Pb^+2][Cl-]^2/[pbcl2]/[Ag^+]^2[Cl]^2/[AgCl]^2
=
[AgCl]^2[pb^+2]/[pbcl2][Ag^+]^2
=
1.85×10−10/(1.13×10−4)^2
=
1.5*10-2