A18 Singlet Oxygen

Description
Chemiluminescent(red) oxygen is formed by the reaction of peroxide and chlorine gas. Red bubbles of singlet oxygen are observed. Color is observed only in the gas bubbles because collisions in the solution phase quench the singlet state rapidly.

Equation
Cl₂ + H₂O₂ --> O₂(singlet) + 2 H⁺ + 2 Cl^-

Reference
B. Z. Shakhashiri, "Chemical Demonstrations", Vol. 1, The University of Wisconsin Press, Madison ,Wisconsin, (1983) p.137.