Posted by
**Kristina** on
.

Calculate the molar solubility of gold(I) chloride (Ksp= 2.0 x 10^-13) in .10 M NaCN. The complex ion formed is [Au(CN)2]- with Kf= 2.0 x 10^38. Ignore any other competing equilibrium systems.

I'm having trouble writing an equation to start off with.

First, I had written

AuCl + NaCN <--> [Au(CN)2]- + NaCl (s)

But I can't seem to balance it correctly.

I think I know how to do the problem if I have just one reactant, but I'm not sure what to do with two. Any help would be appreciated.

The equation is not balanced because the CN- is not balanced. It can be calanced this way.

AuCl + 2NaCN ==> Na[Au(CN)2] + NaCl. In aqueous solution, the sodium salt of the complex ion will ionize into Na^+ and Au(CN)2^- while the NaCl will ionize into Na^+ and Cl^-.