Description of experiment
Below follows a plain text transcript of the selected experiment.
Needed compounds:
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methanol : CH3OH
phosphorus pentachloride : PCl5
niobium pentachloride : NbCl5
Class:
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elem=C,P,Cl,Nb
acid/base
Summary:
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Niobium pentachloride does react with methanol, but not nearly as violently as
phosphorus pentachloride.
Description:
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Sequence 1:
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Add some solid NbCl5 to some methanol: The solid slowly dissolves and a gas is
produced. The liquid becomes colorless, when the solid dissolves, the yellow
color disappears. All NbCl5 dissolves and the final result is a colorless
liquid and a colorless gas.
Add the resulting liquid to water: All of the liquid mixes with the water, and
a clear and colorless solution is obtained. Apparently, the NbOCl3, formed in
the reaction, does not hydrolyse at once.
Sequence 2:
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Add some solid PCl5 to some methanol: An extremely violent reaction occurs. The
solid piece of PCl5 violently skirts over the surface of the methanol and it
only takes a few seconds to dissolve a piece of PCl5 with a diameter of 3 mm.
Remark:
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Both NbCl5 and PCl5 react with methanol, giving CH3Cl, and the other product
being NbOCl3 resp. POCl3. The reaction with NbCl5 is much slower.