Question
Sat August 11, 2012 By: Balaraman Saptharishi

Why Agcl is soluble in NH3

Expert Reply
Sat August 11, 2012
AgCl is an insoluble or sparingly soluble salt. The following equilibium exists when AgCl is added in to water:
AgCl(s) <--> Ag+(aq) + Cl-(aq) --(1)
Since AgCl is insoluble, the equilibrium lies to the left.

In aq NH3, :NH3 acts as a ligand and forms a complex with Ag+ :
Ag+(aq) + 2NH3(aq) <-->[Ag(NH3)2]+ (aq) --(2)

Reaction(2) lowers the concentration of Ag+ and shifts the equilibrium of (1) to the left, dissolving AgCl.
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