Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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hydrochloric acid : HCl
phosphorus red : P
sodium chlorite : NaClO2
Class:
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elem=P,Cl
redox
Summary:
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This is a spectacular experiment. A mix of sodium chlorite and red phosphorus
can be ignited by bringing it in contact with hydrochloric acid.
Description:
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Take a small spatula of finely powdered dry sodium chlorite and take half the
volume of finely powdered red phosphorus. Mix both chemicals, using a petri
dish, which is swirled carefully, such that the two chemicals mix.
Do not transfer the mix of chemicals, just keep the petri dish tilted and tap
it on a work bench, such that the mix of chemicals goes to one side of the
petri dish.
Take an object like a die and let the petri dish stand one side on the die and
the other side with the mix of chemicals on the work bench. The petri dish is
tilted in this way.
Now put a few drops of concentrated hydrochloric acid on the high part of the
petri dish (e.g. using an eye dropper), such that the acid slowly moves towards
the mix of red phosphorus and sodium chhlorite, and finally touches it. Assure
that you step back before the acid touches the mix of chemicals.
As soon as the acid comes in contact with the mix of chemicals, there is a
brief moment of hissing and then the mix deflagrates with a bright orange flame
and a lot of nearly odorless smoke.
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In this experiment, the hydrochloric acid and sodium chlorite react to form
ClO2, which in contact with the red phosphorus causes ignition. The mix of red
phosphorus and sodium chlorite then can burn on its own, somewhat like black
powder.
DO NOT SCALE UP THIS EXPERIMENT AND DO NOT CRUNCH A MIX OF RED PHOSPHORUS AND
SODIUM CHLORITE.