A29 Two Color Clock Reaction

Description
Pyrogallol reacts with hydrogen peroxide vigorously evolving a large amount of gas (carbon dioxide, hydrogen and oxygen) When the temperature increases from the heat of reaction of the pyrogallol, luminol reacts with hydrogen peroxide. First, the reaction is shown with normal lighting for observation of color changes and bubbles. Then, the same reaction is observed in the dark where red light is emitted by the pyrogallol reaction and blue light is emitted by the luminol reaction. The pyrogallol reaction is similar to one used for quantitative analysis of formaldehyde.

Equation
Experimental data are not available for complete reactions.

Reference
B. Z. Shakhashiri, "Chemical Demonstrations", Vol. 1, The University of Wisconsin Press, Madison ,Wisconsin, (1983) p.175.