Question

Consider a mixture of CdS (s) and NaCN (aq). At equilibrium, what would you expect to see? Kf for Cd(CN)42- = 7.1×1026

Essentially the same amount of CdS (s) at the bottom of the mixture.
Most of the solid gone, with a little bit left in the mixture.
All of the solid gone.
There is not enough information to answer this question.

Answer 1

Equilibrium for one step mechanism
A2 + B2 = 2 AB
Rate forward = Kf [A2] [B2]
Rate reverse = Kr [AB] 2
At equilibrium
Rate forward = Rate reverse
Kf [A2] [B2] = Kr [AB] 2
K = (Kf / Kr) = [AB] 2/ [A2] [B2] = Products / Reactants
We need to know the Kr to answer the question
Answer: There is not enough information to answer this question.