Question

for the complex ion equilibria between AgCl and NH3, why does NH3 replace Cl- and how do we know that we have to add 2 infront of NH3? Is the product a salt compound?

Ag + 2NH3= Ag(NH3)2+

Answer 1

The NH3 doesn't replace the Cl-. AgCl is not very soluble. The AgCl that does dissolve solvates with water forming in solution Ag(H2O)2+ and Cl-. (the 2 is a subscript) The NH3 coordinates more strongly than water, so the NH3 replaces the coordinated water. The compound that actually forms is Ag(NH3)2Cl. (again, the 2 is a subscript)