A28 Ammonia Oxidation Catalyzed by Platinum

Description
A platinum coil is used to catalyze the oxidation of ammonia to nitric oxide. Air is flushed over the surface of concentrated ammonia, and the mixture is swept over a platinum coil. The products bubble through a trap. After initiating the reaction, the platinum glows from heat generated by the exothermic reaction. The brightness of the coil is related to the bubbling rate which we hear. Sound is important for this experiment.

Equation
4 NH₃ + 5 O₂--> 4 NO + 6 H₂O

2 NO + O₂ --> 2 NO₂

Reference
H. N. Alyea and F. B. Dutton, Eds.,"Tested Demonstrations in Chemistry", 6th ed., Journal of Chemical Education, Easton, Pennsylvania (1965) p.224, 38.

B. Z. Shakhashiri, "Chemical Demonstrations", Vol. 2, The University of Wisconsin Press, Madison ,Wisconsin, (1985) p.215.