Two-color chemoluminescence

The world of chemical events resembles a stage on which an unbroken succession of scenes is played out. The cast consists of the elements. Each is assigned its unique role, be it that of walk-on or principal character. 

luminol, K2COJ, pyrogallol, 30% H2O2 solution, distilled water, dilute hydrochloric acid. 

The chemoluminescence of luminol has been explained in Experiment 65. The red coloration is due to the formation of singlet oxygen during the oxidation of pyrogallol and formaldehyde by the aqueous H2O2 solution. 

The solution is neutralized with dilute hydrochloric acid and transferred to the container used for collecting water-soluble organic solvents. 

Shakhashiri, Chemical Demonstrations. A Handbook for Teachers of Chemistry, University of Wisconsin Press, Madison, London, 1983, 1, 175. 

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