474 PRACTICAL ORGANIC CHEMISTRY substance will have to be introduced into the combustion tube in order to prevent these acid oxides from reaching the soda-lime in the absorption tube. This is effected by replacing the 200 mm. length of M.A.R. ''wire-form" copper oxide with a 1:1 mixture of the oxide with M.A.R. lead chromate in fine granules. The oxides of sulphur are then converted to non-volatile lead sulphate and so prevented from passing out of the tube and reaching the absorption train. Burning out of combustion tube. The combustion tube L and also the materials with which it has been filled, have not been specially dried in any way and it is now necessary to burn out the com-bustion tube and packing till no more water vapour or carbon dioxide can be driven off. To do this the side-arm H (Fig. 85) is attached to the end of the purification train G in the usual way (the bung J being in place). This joint should be made really tight fitting and there should be no need to disturb it subsequently until either the purification train
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.