Microscale Gas Chemistry: Preparing Bromine Water
Microscale Gas Chemistry: Preparing Bromine Water
Microscale Gas Chemistry: Preparing Bromine Water
Glass bottle with screw cap, label the bottle “Br2(aq)” This bottle must
have a capacity of about 100-mL
50-mL water (preferably distilled water)
a bottle of liquid bromine
Transfer the water to the bottle. Working in a fume hood, decant the vapors
only from a bottle of liquid bromine to the bottle with the water. The vapors
are red in color and heavier than air. After the airspace above the water in the
bottle is filled with red bromine vapors, cap both bottles. Swirl or gently shake
the bottle containing the water in order to mix the contents. The bromine will
readily dissolve and the solution will become yellow in color. The process
should be repeated at least once more. Typically bromine water should be
orange in color so that it can be seen when diluted.
Dissolve the NaBr in the HCl and transfer to the labeled bottle. Add the
sodium hypochlorite to the bottle and swirl to mix the reagents. Keep the
bottle capped when not in use.
Disposal.
Excess bromine water can be ‘neutralized’ to harmless bromide by reacting
it with a few drops of 1 M sodium bisulfite solution or 1 M sodium thiosulfate
solution. Add either of these solutions with stirring until the red color of the
bromine water becomes colorless.