Description of experiment
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Needed compounds:
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hydrogen peroxide : H2O2
hydrochloric acid : HCl
sodium hydroxide : NaOH
phenidone : C6H5 N N C(OH) CH2 CH2
Class:
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elem=C
redox
Summary:
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Phenidone is oxidized by air, but is much less susceptible to oxidation
than developers, such as hydroquinone, pyrogallol.
Description:
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Dissolve some phenidone in water: The liquid is pale pink.
Add some solid NaOH: The solid dissolves and the liquid turns darker and
remains pink and clear. Solid pieces of phenidone, which are moistened with
the NaOH-solution are covered with a red compound which easily dissolves,
when more water is added.
Surprisingly, after standing a while, the liquid has turned pale yellow.
Add an excess amount of HCl (10% by weight): The liquid turns a little darker
and its color changes to grey.
Add a little amount of H2O2 (3% by weight): The liquid first becomes yellow/
orange. After a while it turns darker and its final color is orange/brown,
resembling a strong solution of bromine in water.