Dewar flask test described

The apparatus consists of a stirred 11 Dewar flask with a lid (see Fig. A3.1). The stirrer impeller consists of angled blades and is rotated at a speed which ensures that the surface of the contents is agitated throughout the test. The level of insulation of the apparatus is such that the rate of heat loss is within the limits described in section A.5 below. The temperature of the contents is measured using a thermometer or recording thermocouple, immersed 60 mm below the static meniscus. 

Place the second 20 x 150-mm test tube containing NO2 into the l hexanol slush bath contained in the 250-mL Dewar flask. Examine the tube periodically while allowing it to cool for a few minutes. Describe what you observe in TABLE 38.IF. 

Remove the stopper of the third 20 x 150-min test tube containing NO, swing the test tube (mouth forward) through the air, and replace the stopper. Place the test tube in the l-hexanol slush bath contained in the Dewar flask, and allow the test tube to cool for a few minutes. Remove the test tube, wipe it free of frost and of solvent with a tissue, and note carefully its contents. Describe in TABLE 38.IH what you observe on the sides of the test tube. Any blue liquid is N2O3. 

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