Question

A 130.0 −mL sample of a solution that is 2.8×10−3 M in AgNO3 is mixed with a 230.0 −mL sample of a solution that is 0.12 M in NaCN.

After the solution reaches equilibrium, what concentration of Ag+(aq) remains? Express your answer using two significant figures.

Answer 1

Ksp of AgCN = 5.97×10^–17

concentration of AgNO3 = 130 x 2.8 x 10^-3 / (130 + 230)

                                       = 1.01 x 10^-3 M

concnetation of NaCN = 230 x 0.12 / 130 + 230

                                   = 0.0767 M

AgNO3    + NaCN    ------------------->   AgCN   + NaNO3

1                   1

1.01 x 10^-3        0.0767          

here limiting reagent is Ag+ .

remaiinig CN- = 0.0767 - 1.01 x 10^-3 = 0.0757 M

AgCN    ---------------> Ag+   +   CN-

Ksp = [Ag+][CN-]

5.97×10^–17 = [Ag+] [0.0757]

[Ag+] = 7.9 x 10^-16 M