Here's a breakdown of the reaction:
1. Formation of a soluble complex:
* When ammonia is added to a suspension of silver bromide, the ammonia molecules react with the silver ions (Ag⁺) on the surface of the AgBr crystals.
* This reaction forms the diamminesilver(I) complex ion ([Ag(NH₃)₂]⁺), which is soluble in water.
2. Equilibrium:
* The reaction between AgBr and ammonia is an equilibrium reaction. This means that the formation of the complex ion is reversible.
* The equilibrium lies to the right, meaning that a significant amount of the AgBr will dissolve to form the complex ion.
3. Overall reaction:
The overall reaction can be represented as follows:
```
AgBr(s) + 2 NH₃(aq) ⇌ [Ag(NH₃)₂]⁺(aq) + Br⁻(aq)
```
Consequences of the reaction:
* This reaction is important in photography, where silver bromide is used as a light-sensitive material.
* The formation of the diamminesilver(I) complex ion allows for the dissolution of silver bromide during the developing process.
* The presence of ammonia in the developing solution helps to prevent the formation of silver sulfide, which can cause fogging in photographic images.
Note: The reaction between silver bromide and ammonia is also used in analytical chemistry for the determination of silver.
