1. Formation of the diamminesilver(I) ion:
* AgCl, a white solid, is insoluble in water.
* When ammonia is added, it reacts with the silver ions (Ag⁺) present in the solid AgCl.
* Two ammonia molecules coordinate with each silver ion, forming the diamminesilver(I) ion, [Ag(NH₃)₂]⁺. This complex ion is soluble in water.
2. The overall reaction:
The overall reaction can be represented as follows:
```
AgCl(s) + 2 NH₃(aq) ⇌ [Ag(NH₃)₂]⁺(aq) + Cl⁻(aq)
```
Explanation:
* The reaction is an equilibrium reaction, meaning it can proceed in both directions.
* The addition of ammonia drives the reaction to the right, favoring the formation of the diamminesilver(I) ion and chloride ions.
* The solubility of AgCl increases in the presence of ammonia due to the formation of the soluble complex ion.
Key points:
* The diamminesilver(I) ion is a colorless complex ion.
* This reaction is used in analytical chemistry to dissolve silver chloride precipitates and to separate silver from other metals.
* The reaction is reversible, and the addition of excess acid (e.g., nitric acid) can reverse the reaction, causing the precipitation of silver chloride again.
In summary:
The reaction between silver chloride and ammonia results in the formation of the soluble diamminesilver(I) ion, leading to the dissolution of the silver chloride precipitate.
