CONTINUOUS PROCESS FOR CATALYTIC OXIDATION OF AMMONIA Submitted by: Checked
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Michael P.Olmsted, Wilbraham Academy, Wilbraham, Mass
by: David B.
:Moss, Hiram College, Hiram, Ohio
PREPARATION
Provide apparatus as illustrated (including a coil from an 8-in. length of l't wire and a 500-ml. suction flask), cone NH,, dil FeSO,, H,SO,. DEMONSTRATION
Strongly heat the test tubc at the 13 coil for two or three min, then pull air through the system by means of an aspirator. The air will pick up ammonia and the mixture will pass over the Pt coil; the products will thou bubble through the water in the second test tubc. The wire glows as the gases react, giving evidence of an exothermic reaction at. the catalyst. Products and unrcacted ammonia dissolve in the water. A sample of the resulting solution may be tested for NO by making it slight,lyacid and adding FeS04solution.
REMARKS
The reaction rate may be varied by controlling the flow of air through the system. If the room is partially darkened the visible change in the color of the glowing wire will indicate the variation. See "Tested Demonstrations" 1962 Reprint Edition, pp. 39, 99, 149, 169, and 188.
OPTICAL ROTATION Submitted by:
J . 0. 11 Evans and H. R. Tietze, Newcastle University College, Tighe's Hill, N S W. Australia
Checked by: C. F. Egan, Jr., Kimball Union Academy, Meriden, X. H., and Lawrence Goldthwait, St. George's School, Ncwport, R. I.
PREPARATION
Provide a glass tube 7.5 cm. in diam. X 120 cm. long firmly stoppered a t one end (a 1-liter graduated cylinder may be used with fair results), ring stand and clamps, Polaroid filter, intense light source (such as a slide prolcctor), solution of 900 g sucrose in 900 ml HaO.
of like color (representing 180' rotation of the plane of polarized light) may be measured roughly to  ± cm. For a given wavelength A and temperature t , the specific rotation [a]h' = 10,000 a / c d where a is the angle of rotation in circular degrees (180' here), c the concentration in grams per liter, and d the distance between the bands in cm required for the 180' rotation.
DEMONSTRATION
REMARKS
~ l o u n the t tube in a vertical position and fill i t to within 5 cm of the top. Place the filter over the top of the tube and suspend the projector so that its lens almost touches the filter and its light beam is directed through the length of the tube. If the room is well-darkened a 'rainbow" may be observed from the side of the tube, preferably against a light background Spiral bands of color appear and the spacing between successive bands
The physical set-up is reasonably critical. A tube a t least 6 cm in diameter and 50 cm long and sucrose concentration no less than 900 g/liter favor the most effective appearance of the bands Precise values are not anticipated but the correct order of magnitude for the specific rotation (66 4' for sucrose) is obtainable. Reference: A. Findlay, "Chemistry in the Service of Man," Longmans, Green and Co., London, 1957, p. 204. Journal of Chemical Ed-ucaiion December I964
