Experiments for 'anhydrous chromic acid'
Below follows a summary of all experiments, matching your search. Click one of the EXPERIMENT hyperlinks for a complete description of the experiment.
Results for 'anhydrous chromic acid':
EXPERIMENT 1
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Chromic acid reacts with hydrogen peroxide under formation of a dark blue
compound. When more hydrogen peroxide is added, then apparently the pH of
the liquid becomes too high and other almost black compounds are formed,
which quickly decompose.
EXPERIMENT 2
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It is not possible to make methylammonium chromate or methylammonium
dichromate by mixing solutions of CrO3 and CH3NH2 in water and letting
the solution evaporate. Apparently, chromic acid is not sufficiently
acidic in aqueous solution to protonate the methylamine to a salt.
This is in strong contract with perchloric acid, which, when mixed
with excess methylamine, gives a nice dry solid CH3NH3ClO4 on evaporation.
This also is in strong contrast with ammonia, which gives a mix of
(NH4)2CrO4 and (NH4)2Cr2O7 when excess ammonia and CrO3 are mixed and
allowed to evaporate to dryness.
EXPERIMENT 3
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Hexavalent chromium oxidizes ascorbic acid. This reaction is fast and even
proceeds without adding additional acid. The acidity of the ascorbic acid
suffices to make the reaction proceed quickly.
The resulting chromium(III) forms an intensely colored dull-green complex
(green/grey, almost black at moderate concentration).
EXPERIMENT 4
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Chromium trioxide dissolves well in acetone, but it does not react. When
sulphuric acid is added, then it does react and it can do so nearly
explosively!
EXPERIMENT 5
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Chromium trioxide (CrO3) dissolves in concentrated hydrochloric acid, giving a
dark brown liquid. When this liquid is heated, then some orange/brown chromyl
chloride is formed, which can easily be observed as a vapor above the liquid.
On further heating the hydrochloric acid is oxidized and the hexavalent
chromium is converted to green trivalent chromium.
EXPERIMENT 6
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When phosphorus pentachloride is added to chromium trioxide, then a fairly
vigorous reaction occurs and exchange of oxygen and chlorine atoms occurs. The
two solids react with each other, forming liquid CrO2Cl2 and liquid POCl3.
EXPERIMENT 7
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Sodium sulfite is not capable of reducing CrO3, dissolved in acetyl chloride.
As soon as water is added, the red color of the hexavalent chromium disappears
and green/blue trivalent chromium is formed.
EXPERIMENT 8
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Cesium dichromate is very sparingly soluble in cold water, while cesium
chromate is much more soluble in cold water.
In warm water, the solubility of the dichromate is much higher.
End of results for 'anhydrous chromic acid'