Description of experiment
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Needed compounds:
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ascorbic acid : C6H8O6
sodium chlorite : NaClO2
Class:
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elem=C,Cl
redox
Summary:
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Ascorbic acid and sodium chlorite react violently and the dry mix can even
inflame.
Description:
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Rinse a test tube with some water and then pour out the water again. This makes
the test tube wet on the inside.
Put a little amount of finely powdered solid sodium chlorite in the test tube.
The solid forms a cake on the bottom of the wet test tube.
Add a little finely powdered solid ascorbic acid to the wet sodium chlorite: As
soon as the ascorbic acid touches the wet sodium chlorite, a violent reaction
starts. A hissing sound is produced and yellow gas is produced. The yellow gas
is chlorine dioxide.
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In a petri dish, mix approximately equal amounts of finely powdered sodium
chlorite and finely powdered ascorbic acid. It is important that both chemicals
are perfectly dry! Mixing should be done by swirling the petri dish around.
Move a small part of the mix to one side of the petri dish and hit the mix with
a glass rod or crunch the mix: The mix does not ignite. Apparently, mechanical
agitation or crushing does not ignite the mix.
Move all of the solid material to one pile and put a big drop of water on the
petri dish at a cm distance of the pile of powdered mix. Tilt the petri dish,
so that the drop slowly moves towards the mix: As soon as the water reaches the
pile of powdered mix, a violent reaction starts. The is some crackling and
hissing. Suddenly, the remaining part of the material, which still is dry,
inflames and quickly burns with a bright orange flame, like burning black
powder.