Description of experiment
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Needed compounds:
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ammonium thiocyanate : NH4SCN
sodium nitrite : NaNO2
methanol : CH3OH
hydrochloric acid : HCl
Class:
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elem=N,C
organic
redox
Summary:
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Methanol gives a colorless gas with nitrite in acidic media. No formation
of NO/NO2. This compound probably is CH3ONO, the nitrite ester of methanol.
The large excess of CH3OH does not prevent formation of nitrosyl thiocyanate.
Description:
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Add 1 volume of CH3OH to 3 volumes of 30% HCl: The liquids partially mix.
Shake the liquid: Complete mixing of both liquids. The liquid remains colorless
and a slight amount of heat is produced.
Add some solid NaNO2: There is a fairly vigorous fizzling at the crystals of
NaNO2. The crystals do not dissolve completely, a white finely divided solid
is formed. This probably is NaCl. The evolved gas is completely colorless,
no trace of NO2 can be observed above the liquid. The liquid itself becomes
light yellow and turbid, due to the formation of the white finely divided
solid.
After a while, the fizzling ceases and the liquid remains light yellow.
Add some solid NH4SCN: The liquid becomes deep red/brown. It also starts
fizzling again. No thick white fume is formed above the liquid.
The liquid is turbid, due to a fairly large amount of white solid matter,
this probably is NH4Cl and NaCl.
Dilute the liquid a few times with water: All white solid quickly dissolves,
the liquid produces a colorless gas slowly, the liquid becomes clear and
brown/red.
Heat the liquid to appr. 60 C: The brown/red color becomes less intense.
Bubbling of colorless gas becomes faster.