Detection of the bleaching agent

Give into a test-tube one spatula of washing powder and fill to 1/4 with methanol.
Add a further 1/3 pipette of conc. sulfuric acid.
Warm carefully and ignite the evaporating fumes.

Observation:


Explanation:



Detection of the optical brightener

Take two paper tissues (e.g. handkerchief) and soap one of them with a solution containing an all-in-one-detergent.
Darken the room and hold the light of an UV-lamp (365 [nm]) over the tissues.

Observation:


Explanation:



Detection of the bleaching effect

Preparation for the teacher: Per group prepare 3 pieces of cotton and colourize them with a dye e.g. ink or beetroot extract. Allow for 24 hours having affect on the cotton.

Fill three 400-ml-beakers about half with water. Add to beaker Nr.2 four spatula of sodiumperborate and to beaker Nr.3 the same quantity of all-in-one-detergent.
Warm the beakers to a temperature of ca. 70 – 80 [°C].
Add to each beaker one piece of cotton and allow to wash for at least 10 minutes.
Evtl. move the material by using a glass rod.


Observations:


Explanation: