Chlorine Cleaner - not completely harmless

Demonstration Experiment on Video

Chlorine Cleaner - not completely harmless

Objective: Bleaching Effect of Chlorine

Peter Keusch

German version

Supermarket products:
household cleaner on chlorine basis (Dan Klorix)
beetroot juice
vinegar essence
white coffee filter paper

Glass wares:
Erlenmeyer flask 100 mL
Erlenmeyer flask 250 mL
gas collecting cylinder h = 20 cm d = 5 cm
Pasteur pipette
petri dish d = 9 cm
watch glass d = 8 cm

Experimental procedure:

100 mL of a chlorine cleaner are poured into a gas collecting cylinder. A white coffee filter paper is soaked in beetroot juice and afterwards dried. A small amount of vinegar essence is pipetted to the houshold cleaner (caution: foams!). Then the top of the cylinder is covered with the red colored coffee filter paper.

Results:

The part of the red colored filter paper, which covers the opening of the glass cylinder, turns colorless.

chlorine

Video clip (Download RealPlayer .rm file)

Discussion and background:

Wash-basins, toilets and the floors of bathrooms are cleaned using a strongly alkaline cleaner on sodium hypochlorite basis. (NaOCl). The disenfecting of these cleaners is due to the conversion of hypochlorite to hypochlorous acid, which decomposes to form nascent oxygen (1).

NaOCl in cleaners is dangerous when these cleaners are mixed with cleaners on acid basis. This danger is illustrated by the experiment above. Vinegar liberates chlorine from the hypochlorite containing cleaner (2). Chlorine is responsible for the bleaching of the dye.

Exposure to chlorine gas may cause severe irritation of mucous membranes of the nose, throat, and respiratory tract.
If mixed with ammonia or ammonia-containing household chemicals (drain cleaners, automatic dishwashing detergents, oven cleaners), cleaners on chlorine basis release toxic chloramine gas, which may produce tearing, respiratory tract irritation, and nausea.

Always wear rubber gloves when handling cleaners and use them in well-ventilated areas.

Reference:
G. Schwedt: Experimente mit Supermarktprodukten, Wiley-VCH-Verlag, Weinheim (Germany) 2001

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