Experiments for 'V'
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 'V':
EXPERIMENT 1
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Vanadium (IV) as vanadyl cations, is oxidized by persulfate to vanadium (V)
as pervanadyl.
EXPERIMENT 2
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Vanadium pentoxide hardly dissolves in water. In acid it dissolves slightly
better, but even then its solubility is small.
EXPERIMENT 3
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Vanadium pentoxide can be easily dissolved in acid, when a reductor is
present. Then it is dissolved and at the same time reduced to vanadyl
(vanadium (V) to vanadium (IV)). With very strong reducing compounds,
further reduction to vanadium (III) or even vanadium (II) is possible.
EXPERIMENT 4
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Vanadium (V) builds different kinds of poly-vanadates, with colors ranging
from colorless to deep orange/red.
EXPERIMENT 5
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Vanadyl (vanadium (IV)) does not give a coordination complex with ammonia.
It does not dissolve in ammonia. With stronger bases, a brown vanadate (IV)
compound dissolves (a poly-vanadate (IV) compound??).
EXPERIMENT 6
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Vanadium(III) hydroxide apparently forms a precipitate and does not
dissolve in strongly alkaline liquids.
Vanadium (III) and (IV) are oxidized by peroxodisulfate to vanadium (V).
EXPERIMENT 7
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Hydrogen peroxide builds complexes with vanadium (IV) and vanadium (V)
species. These compounds are not stable and result in dissociation of
the complex and formation of vanadium (IV) compounds. The net result
of adding hydrogen peroxide to a solution containing vanadium (V) can
be reduction to vanadium (IV) with the formation of oxygen.
EXPERIMENT 8
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Peroxodisulfate ([S2O8]2-) is capable of oxidizing vanadyl ([VO]2+) to
pervanadyl ([VO2]+), but this reaction proceeds slowly.
EXPERIMENT 9
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Vanadium (IV) does not build complexes with EDTA in acidic environments.
EXPERIMENT 10
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Vanadium (III) apparently builds a coordination complex with EDTA in
strongly acidic environments. This complex is brown.
EXPERIMENT 11
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Vanadyl builds an intensely colored complex with thiocyanate in acidic
environments. In alkaline environments this complex is destroyed.
When H2O2 is added, this complex is destroyed as well, but in this
case some heating is required.
EXPERIMENT 12
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The vanadyl salt of ferrocyanide does not dissolve in water. The salt is
easily hydrolysed in alkaline environments (it resembles the prussian blue
as far as this behaviour is concerned).
EXPERIMENT 13
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The vanadyl salt of ferricyanide does not dissolve. The differences between
the ferricyanide salt and ferrocyanide salts are not very clear. In alkaline
solution apparently ferricyanide and vanadate (IV) can coexist.
EXPERIMENT 14
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Vanadium (V) compounds can coexist with ferricyanide in solution. Reduction
of either one of them results in formation of a precipitate.
EXPERIMENT 15
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Vanadyl gives diverse complexes with citrate, the color of these complexes
strongly depends on the pH of the solution.
EXPERIMENT 16
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Hydroxyl amine is capable of reducing vanadium (V) to vanadium (IV), but
further reduction is not possible with hydroxyl amine.
EXPERIMENT 17
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It is possible to let a liquid completely solidify by making the correct
precipitates. Citrate is very suitable for this, combined with some
transition metals.
EXPERIMENT 18
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Sulfide reacts with metavanadates, resulting in the formation of a dark
brown/greenish compound.
EXPERIMENT 19
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Vanadyl ions do not precipitate with ferricyanide, when a large excess
amount of oxalic acid is present. Without the presence of oxalic acid
the two compounds form a green/yellow/brown precipitate (see other
experiments).
EXPERIMENT 20
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Vanadium (IV) does not readily yield precipitates with alkaline compounds.
Carbonate is not capable of precipitating this.
Hydrogen peroxide builds a complex with vanadium (V) and possibly with
vanadium (IV). Diverse coloured compounds are formed in sequence. What
is their constitution?
EXPERIMENT 21
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The result of this experiment is remarkable. Hydroxyl amine, being a strong
reductor, appears to oxidize vanadium (IV) to vanadium (V) in alkaline
environments. Or is there another compound, which strongly resembles the
well-known yellow colour of vanadium (V) in acidic environments and the
(almost) colourless appearance of vanadium (V) in alkaline environments?
EXPERIMENT 22
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Vanadyl ions do not form a special complex with tartaric acid in strongly
acidic environments.
When hydrogen peroxide is added, a complex is formed, but is
this due to the presence of tartaric acid?
When tartaric acid is added to a solution of vanadyl sulfate in an
environment, which is only slightly acidic, then a green complex is
formed. On making the liquid more basic, a vague sequence of color
changes occurs, through grey/blue, finally going to brown.
EXPERIMENT 23
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Vanadium pentoxide dissolves in ammonia and when heated a white solid is
formed, probably this is ammonium meta vanadate.
EXPERIMENT 24
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Vanadium pentoxide reacts with ammonia, producing a strong hissing noise.
A white compound is created. This probably is ammonium metavanadate,
NH4VO3.
EXPERIMENT 25
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Oxalic acid does not seem to form a coordination complex with vanadyl ions,
or if a complex is formed, then it has a color, which is almost the same of
the color of aquated vanadyl.
EXPERIMENT 26
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Vanadium (V) compounds form yellow compouds with hydrogen peroxide in
alkaline environments, with strong solutions and very high alkalinity grey
and blue compounds are formed, which, however, decompose easily.
EXPERIMENT 27
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Vanadium pentoxide can be dissolved in very concentrated solutions of NaOH
in considerable quantities. When such a solution is cooled down, then a
white crystalline solid separates from the liquid and the liquid completely
solidifies.
EXPERIMENT 28
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Vanadyl forms a light blue or white compound with phosphates, when it is
precipitated.
In excess alkali, this dissolves, forming a greenish brown clear liquid.
This color is like the familiar brown color of strongly alkaline solutions,
containing vanadium in the +4 oxidation state, but a little bit less reddish
and more greenish.
EXPERIMENT 29
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Vanadyl is oxidized by bromate quickly and completely.
EXPERIMENT 30
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Vanadyl ions apparently do not form a coordination complex with chloride at
extremely high concentration, or the coordination complex has the same color
as the vanadyl-aqua complex.
EXPERIMENT 31
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Vanadium (V) is capable of forming many peroxo compounds, whose appearance
strongly depends on pH.
EXPERIMENT 32
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Without the help of a strong acid, vanadium pentoxide is not capable of
oxidizing formic acid, not even when heated. When some sulfite is added,
then incomplete reduction of the V2O5 can be observed.
With the help of a strong acid and when in solution, vanadium (V) is
capable of oxidizing formic acid, but only very slowly.
With formic acid and vanadium (IV), apparently a coordination complex
is formed. Another explanation is given below at the end of the
description.
EXPERIMENT 33
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Vanadium in the +4 oxidation state is not reduced to vanadium in a lower
oxidation state by borohydride.
EXPERIMENT 34
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Vanadium in its +4 oxidation state forms a blue compound, vanadyl, in acidic
environments. In near neutral to alkaline environments, the situation is
less clear. Reduction of neutral or alkaline vanadium (V) compounds yields
a dark and turbid liquid.
Vanadium in its +5 oxidation state gives light yellow compounds in mildly
alkaline environments. Al lowering the pH, the color becomes more intense,
until a maximum is reached. When the pH is lowered even more, then lighter
yellow compounds are formed again.
Vanadium (IV) cannot coexist with hydrogen peroxide. In alkaline media it
is oxidized to vanadium (V), which with excess peroxide gives a yellow
peroxo complex. In acidic media, vanadium (IV) is oxidized to vanadium (V)
which gives a deep brown/red peroxo complex with excess poroxide.
EXPERIMENT 35
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Vanadium pentoxide dissolves in concentrated sulphuric acid with some heating.
A deep red liquid is formed, which, remarkably, only is reduced by sulfite in
the presence of some water.
EXPERIMENT 36
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When vanadyl sulfate is dehydrated by heating, then the resulting solid only
dissolves partially in water and in dilute acid. When a strong oxidizer is
present, all of the solid dissolves again, forming a soluble vanadium species
in the +5 oxidation state.
EXPERIMENT 37
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Vanadyl ion is not reduced by borane to vanadium in a lower oxidation state.
EXPERIMENT 38
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Hydroquinone is oxidized by chlorate, but this reactions proceeds slowly.
When vanadium pentoxide is added in small quantities, then the reaction
proceeds much faster. The vanadium pentoxide acts as a catalyzer.
EXPERIMENT 39
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Catechol forms a coordination complex with vanadyl.
EXPERIMENT 40
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Vanadium pentoxide catalyzes the oxidation of hydroquinone to quinone by
hydrogen peroxide.
EXPERIMENT 41
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Chromium (III) cannot be oxidized to chromium (VI) by vanadium (V) species
or bromates in strongly alkaline environments. Peroxodisulfate is capable
of achieving this.
EXPERIMENT 42
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Vanadium pentoxide does not seem to react with red phosphorus.
EXPERIMENT 43
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When hydrated sulfate-salts are heated, which only loose water, then their
properties strongly change. The color changes, but also the solubility
properties change a lot. The sulfate salts loose water easily, but no acid
(H2SO4 or SO3).
EXPERIMENT 44
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Vanadium in oxidation state +5 is capable of oxidizing ethanol in acidic
solution, but this reaction is very very slow.
EXPERIMENT 45
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Vanadyl sulfate n-hydrate is dehydrated by hot concentrated sulphuric acid,
giving insoluble solid anhydrous VOSO4. This solid does not dissolve in the
concentrated acid, nor in water.
EXPERIMENT 46
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Vanadium(V) in acidic solution is reduced by hypophosphite to vanadium(IV), but
there is no further reduction to a lower oxidation state.
EXPERIMENT 47
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When a solution of vanadyl sulfate is mixed with excess sodium nitrite, then a
very dark liquid is obtained and some NO is formed. On acidification, this
liquid becomes green/yellow, but on boiling, it becomes blue again and it
appears that all vanadium goes to oxidation state 4 again.
EXPERIMENT 48
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The blue vanadyl ion VO(2+), which contains vanadium in oxidation state +4, is
oxidized by oxone (which contains the monopersulfate ion, SO5(2-)) and it also
is oxidized by the peroxodisulfate ion S2O8(2-). Oxidation by monopersulfate is
immediate, oxidation by peroxodisulfate is very slow. The latter reaction can
be sped up by heating, but still it takes tens of seconds on near boiling of
the solution.
The blue vanadyl ion is oxidized to the pale yellow pervanadyl ion VO2(+). On
heating, this pervanadyl ion condenses into more intensely colored ions which
contain multiple VO2(+) units. At a certain point the condensation of the
pervanadyl ions goes so far that a red/orange precipitate is formed of hydrous
vanadium pentaoxide, V2O5.nH2O.
EXPERIMENT 49
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Vanadium pentoxide does not dissolve in thionyl chloride, but when a small
amount of water is added, then it reacts.
Vanadium pentoxide dissolves in acetyl chloride, giving a dark red/brown
solution.
End of results for 'V'