Silver Chloride Photodecomposition
2AgCl → 2Ag + Cl2
Overview
Silver chloride darkens upon exposure to light as photons provide enough energy to reduce Ag⁺ to metallic silver. This photosensitivity of silver halides is the fundamental chemistry behind traditional photography. The released chlorine atoms combine to form Cl₂ gas.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Silver Chloride AgCl | 2 | (s) |
| Product | Silver Ag | 2 | (s) |
Everyday Example
Traditional black-and-white photography relied on this reaction — light hitting AgCl-coated film created a latent image of metallic silver.
Industrial Importance
Silver halide photography dominated imaging for 150 years. AgCl is still used in photochromic lenses that darken in sunlight.
Properties
- Type
- Photochemical
- Reversible
- No
- Energy
- Endothermic
- ΔH
- 254.0 kJ/mol
Related Reactions
Chlorophyll Fluorescence
Cis-Trans Isomerization of Retinal
Dye-Sensitized Solar Cell (Grätzel Cell)
Firefly Bioluminescence (Luciferin Oxidation)
Luminol Chemiluminescence
Ozone Decomposition by UV
Ozone Formation by UV Light
Photocatalytic NOx Removal
Photocatalytic Water Splitting (TiO₂)
Photochemical Cycloaddition ([2+2])
Frequently Asked Questions
What is the equation for Silver Chloride Photodecomposition?
The balanced equation is: 2AgCl → 2Ag + Cl₂.
What type of reaction is Silver Chloride Photodecomposition?
Silver Chloride Photodecomposition is a photochemical reaction.
Is Silver Chloride Photodecomposition exothermic or endothermic?
Silver Chloride Photodecomposition is endothermic (absorbs energy). The enthalpy change (ΔH) is 254.0 kJ/mol.