Question

Ag⁺ is complexed by the chelating ligand trien (triethylenetetramine, NH₂(CH₂)₂NH(CH₂)₂NH(CH₂)₂NH₂).

Ag+ + trien ⇌ Ag(trien)+

Kf = 5.0×107

40.8 mL of 0.0273-M trien solution is added to 25.0 mL of 0.0146-M silver nitrate solution.
What is [Ag⁺] at equilibrium?

Answer 1

                              Ag⁺ + trien ⇌ Ag(trien)⁺

             no of moles of trin = molarity * volume in L

                                        = 0.0273*0.0408   = 0.00111moles

          no of moles of AgNo3 = molarity * volume in L

                                               = 0.0146*0.025   = 0.000365 moles

                 Ag⁺    +    trien    ⇌      Ag(trien)⁺

      I        0.000365         0.00111             0

     C       -0.000365      -0.000365           0.000365

    E          0                    0.000745 0.000365

x

Kf = Ag(trien)⁺ /[Ag+][trien]

             5*10⁷   = 0.000365/x*0.000745

            x           = 0.000365/5*10⁷*0.000745    = 9.8*10^-9 M

         [Ag+] = x = 9.8*10^-9 M >>>>> answer