Question

Explain why the formation of the diammine silver(I) complex cation is favored in a basic solution, but not in an acidic solution.

Answer 1

i think this might help you.

Answer 2

A number of slightly soluble salts do not dissolve readily in acids. eg. AgCl will not dissolve in nitric acid.
In order to dissolve AgCl, the equilibrium of AgCl(s) <=====> Ag+(aq) + Cl-(aq)
must be shifted to the right.
Two things can do this:
NH3 or CN- form co-ordinate bonds with the Ag+ ions and remove them from the solution. They create complex ions that are even more insoluble then the original AgCl.
The ammonia solution has Ag(NH3)2+ in it, and the cyanide solution has the Ag(CN)2- ion in it.
These two polyatomic ions are weakly dissociated.

The part of the ion which attaches by a co-ordinate bond is called a ligand.

eg. AgCl(s) + 2 NH3(aq) <======> Ag(NH3)2+(aq) + Cl-(aq)

AgCl(s) + 2 CN-(aq) <=======> Ag(CN)2- + Cl-(aq)