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Anthocyanin plant pigments such as those found in red cabbage have been extracted and used as an acid-base indicator in many educational and entertaining demonstrations (1-5). Approximate pH ranges have been listed (2, 3, 5). This paper extends the use of the red cabbage extract into demonstrations that illustrate the acidic or basic nature of solutions of gases and gives suggestions for modifications to project the beautiful range of colors and shades for better viewing in large lecture halls.

The explosion or burning of methanol, ethanol, n-propanol, and isopropanol in large small-necked bottles when ignited with a match has been studied with respect to the nature of the alcohol, temperature, concentration dilutions with water, oxygen concentration, plastic versus glass bottles, and salts added for color. The various effects are explained in terms of vapor pressures. Safety guidelines are emphasized.

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Articles you may be interested inSinglecrystal electron paramagnetic resonance study of triplet excitons in [Fe(mesitylene)We have studied the electron paramagnetic resonance spectra of Mn(CN)oN()2-and Cr(CNhN()2as dilute solutions in single crystals of various diamagnetic hosts. From these measurements, we have obtained the spectroscopic splitting factor tensor and the hyperfine tensors to the central metal atom and nitrosyl nitrogen. In the case of Cr(CNhNOa-, we have also measured the hyperfine tensor to carbon-13 in the equatorial and axial cyanides. We have measured the quadrupole coupling constant to 5iMn in Mn(CN).NOi!-. We have attempted to construct a coherent picture of the electronic structure of the complexes from these data. This attempt has been only partly usccessful, primarily because the spectroscopic splitting factors are much nearer the free spin value than one expects on the basis of the hyperfine data. 11 J. Danon and H. C. Panepucci (personal communication).