214 ELEMENTS OF GROUP IIIextreme violence that it is safe to let the vapor only of bromine
come in contact with the metal.
Aluminum bromide melts at 97.5° and boils at 268°. It is very
soluble in carbon disulphide without chemical action. It reacts
explosively with water, and throughout this preparation extreme
caution must be observed not to let any of it come in contact with
water.Materials: aluminum turnings, 9 grams = 0.33 F.W.
bromine, 80 grams = 25 cc. (must be dry and must
be measured in a dry graduate),
carbon disulphide.
Apparatus: two 125-cc. distilling flasks.
125-cc. separatory funnel.
600-cc. beaker.
3 clean dry test tubes.
18 inches hard glass tube of 15-mm. diameter.
360° thermometer,
burette clamp,
ring stand.
Bunsen burner.Procedure: This preparation must be carried out entirely under
the hood. Fit the separatory funnel with a rubber stopper into
one of the distilling flasks; clamp the latter upright with the bulb
immersed in water in a 600-cc. beaker on a ring stand. Fit the
side arm of the distilling flask with a rubber stopper into one end
of the hard glass tube. The other end of this tube should be
thrust loosely into the neck of the other distilling flask. Place the
aluminum turnings about in the middle of the hard glass tube.
The tube should slope downward toward the receiving flask but
not so much that the aluminum will not remain in place. The
entire apparatus must be absolutely dry inside. Transfer the
bromine to the separatory funnel. Heat the water in the beaker
to boiling, and regulate the flame so that it continues to boil
gently. Open the stop cock of the dropping funnel and let the
bromine drip very slowly into the heated flask and vaporize. Heat
the aluminum in the hard glass tube until it begins to glow; then
regulate the dripping of the bromine to keep up a vigorous reaction.
The reaction will now be self-sustaining if the bromine is per-