When aqueous silver nitrate solution is exposed to light, it undergoes a photochemical decomposition reaction. This results in the formation of metallic silver (Ag), nitric acid (HNO₃), and oxygen gas (O₂).

Here's the chemical equation for the reaction:

2AgNO₃ (aq) → 2Ag (s) + 2HNO₃ (aq) + O₂ (g)

Here's what happens:

* Light energy provides the activation energy for the reaction.

* Silver nitrate (AgNO₃) is a white crystalline solid that dissolves in water to form a colorless solution.

* Metallic silver (Ag) is formed as a dark, solid precipitate. This is why you often see a darkening of the solution or the formation of a black deposit in the container.

* Nitric acid (HNO₃) remains in solution.

* Oxygen gas (O₂) is released as bubbles.

The reaction is sensitive to the intensity and wavelength of light. Ultraviolet light is particularly effective in promoting this decomposition. This is why silver nitrate solutions are typically stored in dark brown bottles to protect them from light.