Quickly put a stopper onto the test tubes. Hold the test tubes in the light for about 30 seconds or until orange bromine color fades to colorless. Remove both test tubes, holding them up for the class to compare. Beware Bromine is an extremely strong oxidizer and will burn skin terribly. Wear gloves and goggles and prepare the bromine solution in a hood.
Bromine vapors are dangerous.
Keep bromine solution covered during demonstration. The Sodium Thiosulfate solution should be used to neutralize bromine. Neutralize any spills of bromine immediately and rinse any glassware that held bromine with the Sodium Thiosulfate solution. Glacial Acetic Acid is concentrated and will irritate skin. Wear gloves and safety goggles.