Table of Contents
In the preparation of bromine, fix up your apparatus as for the preparation of nitric acid, surrounding the receiver with cold water. Mix about 4 grams of manganese dioxide with 2 grams of potassium bromide, transfer to the retort carefully, and add a little strong sulphuric acid; then replace the stopper in the retort and heat gently. Dark red fumes fill the retort, and a heavy dark red liquid condenses in the receiver. Collect a few c.c. of the liquid.
2KBr + 2H2SO4 + MnO2 = K2SO4 + MnSO4 + 2H2O + Br2.
Laboratory Bromine Gas Experiment I
Take a few drops of bromine in a beaker and add about thirty times as much water; shake the mixture well, and a clear yellowish- red solution will be obtained. Dip a piece of madder-dyed cloth into this solution; it is bleached, but the action is slower than with chlorine.
Bromine Gas Laboratory Experiment II
Pour a few drops of bromine into a wide-mouthed bottle, warm it gently, and plunge a piece of dry phosphorus on a deflagrating spoon into the bottle; light is evolved, the phosphorus combining so energetically with the bromine.
P + Br3 = PBr3
Laboratory Experiment with Bromine Gas III
Dissolve a few crystals of potassium bromide in water in a test-tube, add a little chlorine water, and shake; the water is turned a yellowish-red colour. Now add some carbon disulphide to the solution and shake well; the bromine is concentrated in the carbon disulphide.
KBr + Cl = KCl + Br