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.