Experiments for 'sulphuric 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 'sulphuric acid':
EXPERIMENT 1
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Nitrite gives rise to formation of a blue compound with dilute sulphuric
acid, which is not very stable (dissociates into nitrous oxide easily).
When bromide is added, then a brown/green compound is formed, which
is not bromine.
EXPERIMENT 2
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Thiocyanate is oxidized by nitrate very violently under the right conditions.
EXPERIMENT 3
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Nitrogen oxides do not dissolve in ligroin. Nitrosyl bromide does. When a
compound with unstaturated C=C bonds is added, then the nitrosyl bromide
does not quickly decompose. It does not react with alkenes and the presence
of alkenes does not cause it to decompose quickly.
EXPERIMENT 4
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Allyl alcohol (having one double bond between carbon atoms) forms a nitrite
ester very easily and this ester is stable, at least for several minutes.
EXPERIMENT 5
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Vanadium (IV) as vanadyl cations, is oxidized by persulfate to vanadium (V)
as pervanadyl.
EXPERIMENT 6
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Vanadium pentoxide hardly dissolves in water. In acid it dissolves slightly
better, but even then its solubility is small.
EXPERIMENT 7
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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 8
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Vanadium (V) builds different kinds of poly-vanadates, with colors ranging
from colorless to deep orange/red.
EXPERIMENT 9
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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 10
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Peroxodisulfate ([S2O8]2-) is capable of oxidizing vanadyl ([VO]2+) to
pervanadyl ([VO2]+), but this reaction proceeds slowly.
EXPERIMENT 11
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Vanadium (IV) does not build complexes with EDTA in acidic environments.
EXPERIMENT 12
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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 13
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Vanadyl gives diverse complexes with citrate, the color of these complexes
strongly depends on the pH of the solution.
EXPERIMENT 14
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Sulfide reacts with metavanadates, resulting in the formation of a dark
brown/greenish compound.
EXPERIMENT 15
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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 16
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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 17
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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 18
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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 19
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Vanadium pentoxide dissolves in ammonia and when heated a white solid is
formed, probably this is ammonium meta vanadate.
EXPERIMENT 20
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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 21
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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 22
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Vanadium in the +4 oxidation state is not reduced to vanadium in a lower
oxidation state by borohydride.
EXPERIMENT 23
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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 24
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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 25
---------------
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 26
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Copper (II) reacts with thiocyanate in a complex way.
EXPERIMENT 27
---------------
Copper builds higher oxides than CuO when strong oxidizing agents are
present in alkaline environments. Probably these are not copper (III)
compounds, but the oxo-ion probably is replaced by peroxo or superoxo.
EXPERIMENT 28
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Copper tetrammine sulfate only dissolves very slowly in not too strongly
diluted sulphuric acid.
EXPERIMENT 29
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Copper (II) ions form a brown complex with bromide ions, but only when the
product of concentration of copper and bromide is high.
In strongly acidic environments, bromide gives a red/brown/purple complex
with cupric ions.
EXPERIMENT 30
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Nitrous acid (or its decomposition product) forms a dark brown coordination
complex with ferric ions. With copper (II) also a coordination complex is
formed. In relatively strongly acidic environments, these coordination
complexes are destroyed/not formed.
EXPERIMENT 31
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Copper (II) does not form a coordination complex, nor does it form a
precipitate with bromate. It does not react.
EXPERIMENT 32
---------------
Copper (II) is reduced by metabisulfite / sulphur dioxide to a copper (I)
compound, but some heating is required in order to make this reaction
fast.
EXPERIMENT 33
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Cupric chloride dihydrate is dehydrated by concentrated sulphuric acid.
EXPERIMENT 34
---------------
Cupric chloride dihydrate dissolves in acetone. The solution becomes yellow
at low concentrations, green/brown at higher concentrations. When sulphuric
acid is added, then a precipitate of anhydrous cupric chloride is formed.
EXPERIMENT 35
---------------
Nitrite forms a dark green coordination complex with copper (II) ions in
neutral environments. When acidified, then a new coordination complex
(dark blue with a grey hue) is formed in the presence of chloride of
very high concentration. This is not formed when chloride is absent.
EXPERIMENT 36
---------------
Copper (II) ions are complexed by EDTA Na4, but when the liquid is acidified,
then the copper ions are not coordinated anymore.
EXPERIMENT 37
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Copper (II) forms a very dark coordination compound with concentrated
bromide in highly acidic environments. When metallic copper is added,
then this complex quickly disappears and the liquid almost becomes
colorless.
EXPERIMENT 38
---------------
Borohydride is capable of reducing copper to its metallic state.
EXPERIMENT 39
---------------
Copper hydroxide easily looses water, when it is heated, even if it is
completely covered with water.
EXPERIMENT 40
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Copper (I) oxide, when added to sulphuric acid, disproportionates. Metallic
copper is formed and a blue solution of copper (II) sulfate. The copper (I)
oxide looses its oxide ion to the acid and that would leave aqueous copper (I)
ions. These are not stable and disproportionate at once.
Copper (I) oxide, added to hydrochloric acid dissolves and forms a solution,
containing a copper (I) complex, [CuCl2]-. This complex is very easily oxidized
by oxygen from the air and then a dark brown mixed valency complex of copper
(I) and copper (II) is formed.
EXPERIMENT 41
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Zinc (II) gives a white precipitate with ferrocyanide. This precipitate
becomes pale yellow, when treated with hydrogen peroxide (at least, when
in acidic environment).
EXPERIMENT 42
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Cobalt (II) is stable in acidic environments, but in alkaline environments
in the presence of ammonia it reacts with oxygen from the air, resulting
in the formation of a dark red/brown coordination complex.
EXPERIMENT 43
---------------
Cobalt carbonate does not dissolve completely in dilute mineral acids. With
some heating, however, it does dissolve completely.
With nitrite a yellow/orange complex is formed, which forms a precipitate
when treated with alkalies. The precipitate is resistant to treatment with
acid and bases.
EXPERIMENT 44
---------------
Cobalt sulfide does not dissolve in dilute acids and it does not dissolve
in concentrated hydrochloric acid (at least not easily). With the help of
hydrogen peroxide it is possible, however, to dissolve the compound.
EXPERIMENT 45
---------------
Cobalt (II) gives a green precipitate with ferrocyanide and a dark red/
purple precipitate with ferricyanide. The green precipitate cannot be
converted to the red one by means of oxidation by hydrogen peroxide, but
another, dark blue, compound is formed.
EXPERIMENT 46
---------------
The hexanitrito cobaltate (III) ion is stable towards dilute sulphuric acid.
Addition of hydrogen peroxide also does not destroy the yellow complex.
EXPERIMENT 47
---------------
In this experiment, some of Werner's experiments are repeated. Here it is
shown that cobalt forms beautifully colored carbonato complexes. The exact
complex formed, depends on the experimental conditions. It is remarkable
what kinds of reactions are shown by cobalt in its complexes and it is
really difficult to precisely determine what is happening and it even is
difficult already to get the same results without precisely specifying the
exact experimental conditions (e.g. using HCl instead of H2SO4 already
results in a different outcome).
EXPERIMENT 48
---------------
Cobalt (II) chloride hexahydrate is a red/purple compound. When it is heated,
it becomes blue, first dark blue, lateron much lighter blue. The latter
compound is anhydrous cobalt (II) chloride.
Anhydrous cobalt (II) chloride dissolves with a deep blue color in DMSO. With
nitrite, apparently no complex (or a complex with the same color) is formed,
the solution remains deep blue.
The anhydrous cobalt (II) chloride also dissolves in water without problems.
Such solutions are pink. With nitrite these form yellow complexes on
acidification.
Anhydrous cobalt (II) chloride is not soluble in nitromethane.
EXPERIMENT 49
---------------
Sulphur dissolves in hot solutions of sodium hydroxide and disproportionates
in a way, similar to disproportionating of halogens.
When acetone is added, a peculiar blue/green compound is formed in the
acetone. What is this compound?
EXPERIMENT 50
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Thionyl chloride is not soluble in concentrated sulphuric acid, or only
sparingly soluble.
The mix of thionyl chloride and sulphuric acid is capable of forming chromyl
chloride from potassium dichromate.
EXPERIMENT 51
---------------
In strongly alkaline environments, molybdates are not as easily reduced
as in neutral or acidic environments.
EXPERIMENT 52
---------------
Molybdates and phosphates produce a yellow complex in an anion, containing
both molybdenum and phosphorus. This complex is slowly reduced by sulfite.
EXPERIMENT 53
---------------
Molybdate gives rise to all kinds of complexes, when combined with reducing
agents. These complexes can be yellow, green or blue. The composition of
all these complexes is not very clear.
EXPERIMENT 54
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Molybdenum trioxide dissolves well in strongly alkaline liquids. It does
not dissolve (or just a little bit) in plain water. Once dissolved, it
can be kept in solution, even when pH is lowered.
Molybdates are capable of oxidizing iodide and sulfite.
EXPERIMENT 55
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Molybdate forms strongly colored, but unstable, complexes with hydrogen
peroxide.
EXPERIMENT 56
---------------
Molybdate forms blue or green compounds, when reduced with mild reducing
agents or when little quantitities of reducing agents are used.
EXPERIMENT 57
---------------
Ammonium molybdate forms a yellow coordination complex with phosphates in
acidic environments, which precipitates. Oxidizing compounds do not
dissolve this precipitate, alkaline compounds do dissolve this precipitate.
EXPERIMENT 58
---------------
Molybdates and orthophosphates give a yellow complex, which is reduced more
easily than molybdates alone.
EXPERIMENT 59
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When molybdate (VI) is reduced by a small amount of reductor, then a blue
compound is formed. When a larger amount of reductor is available, then a
black compound is formed.
EXPERIMENT 60
---------------
Diverse phenol-derivatives, can be oxidized easily by bromine, yielding
intensely colored oxidation products.
EXPERIMENT 61
---------------
Phenidone can be oxidized by potassium dichromate and the oxidation
product appears to be a solid, dark brown compound, which does not
dissolve in water.
EXPERIMENT 62
---------------
Benztriazole cannot be oxidized by acidified dichromate. Metol is
quickly oxidized.
EXPERIMENT 63
---------------
When p-aminophenol is oxidized in an acidic environment, then a compound
is formed, with a deep indigo/purple color.
EXPERIMENT 64
---------------
Both metol and p-aminophenol HCl are oxidized by persulfate to colored
compounds. When metol is used, the color, however, is not as brilliant
and not as intense as when p-aminophenol HCl is used. Apparently the
methyl-group on the amino-part of metol has strong influence on the
color of the oxidation product or on the type of oxidation products.
EXPERIMENT 65
---------------
When p-aminophenol is oxidized in acidic environment, then an intensely
colored compound is formed (indigo/purple). This compound is irreversibly
destroyed when the liquid is made alkaline.
EXPERIMENT 66
---------------
Pyrogallol reacts with chlorine, forming an orange/red compound. When excess
chlorine is used, this compound is further oxidized to an almost colorless
compound.
EXPERIMENT 67
---------------
P-aminophenol, when oxidized, forms a deeply colored compound. The color
of this compound is deep blue/purple, but the environment and the used
oxidizer have some influence on the color of the liquid as a whole (other
compounds may make the color less pure).
EXPERIMENT 68
---------------
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 69
---------------
Catechol forms a coordination complex with vanadyl.
EXPERIMENT 70
---------------
Vanadium pentoxide catalyzes the oxidation of hydroquinone to quinone by
hydrogen peroxide.
EXPERIMENT 71
---------------
It is possible to make an aqueous solution of bromine, which is so saturated,
that the bromine separates from the liquid. In order to do so, a chemical
reaction, producing large quantities of bromine must be performed.
EXPERIMENT 72
---------------
Sodium chloride reacts with sulfuric acid to give hydrogen chloride gas.
Sodium bromide shows a similar reaction, producing hydrogen bromide, but
in a side reaction some bromine is formed.
EXPERIMENT 73
---------------
When potassium chlorate and concentrated sulphuric acid are mixed, a very
dangerous and strong oxidizer is created, which reacts explosively with
organic matter.
EXPERIMENT 74
---------------
Bromide is oxidized by sulphuric acid, even when diluted with water.
Bromine precipitates from water, when it is created in high concentrations.
EXPERIMENT 75
---------------
Sodium chlorate reacts with chloride in acidic environment, forming chlorine
(which can be detected by means of its odour) and a fairly intensely colored
yellow gas (chlorine dioxide). The color of this gas is much more intense
than the color of chlorine.
The yellow compound is destroyed by sulfite and nitrite.
EXPERIMENT 76
---------------
Bromate reacts with concentrated sulphuric acid, releasing bromine and a
gas (probably this is oxygen).
EXPERIMENT 77
---------------
Bromate is reduced by sulfite quickly in acidic environments. When an
excess amount of bromate is used, then bromine is formed. When an excess
amount of sulfite is used, then the bromine is reduced further to bromide.
EXPERIMENT 78
---------------
Potassium bromate is capable of oxidizing hydrogen peroxide, itself being
reduced to bromine.
EXPERIMENT 79
---------------
Although the redox potential from bromate to bromine is higher than the
potential from perchlorate to chlorate, when chlorate and bromate are
mixed, then no reaction occurs. When some hydrochloric acid is added,
then a reaction occurs with the chloride ions.
EXPERIMENT 80
---------------
A mixture of chlorine and chlorine dioxide oxidizes bromide quickly to
bromine. When an excess amount of nitrite is added, then the bromine is
quickly reduced again to bromide. Addition of an acid does not result in
formation of bromine again.
EXPERIMENT 81
---------------
A large amount of sulphur can be added to bromine, before a solid remains in
the liquid bromine. The sulphur dissolves in the bromine very easily.
EXPERIMENT 82
---------------
Bromates are more reactive than chlorates in dilute aqueous solutions.
EXPERIMENT 83
---------------
Bromate reacts with chlorides, releasing chlorine. Probably some bromine
is produced as well or a bromine/chlorine compound is produced.
EXPERIMENT 84
---------------
Bromate oxidizes iodine to iodate, itself being converted to bromine.
Chlorate does not oxidize bromine to bromate, itself being converted to
chlorine (at least not quickly).
EXPERIMENT 85
---------------
Potassium tetrachloroiodide decomposes on heating. The residue, which
remains behind is potassium chloride.
EXPERIMENT 86
---------------
Aluminium reacts violently with bromine.
EXPERIMENT 87
---------------
TCCA does not react with sulphuric acid, at least not visibly. Even when
heated, no reaction seems to occur. On addition of some solid NaCl vigorous
evolution of chlorine gas is observed.
EXPERIMENT 88
---------------
Chlorite ion forms complexes with cobalt(II) and copper(II). It forms a
precipitate with lead(II). The precipitate with lead(II) forms a highly
energetic compound.
EXPERIMENT 89
---------------
When concentrated sulphuric acid is added to concentrated nitric acid,
then some heating can be observed.
The mixed acid reacts with tissue, but not as strongly as pure sulphuric
acid does. The mixed acid reacts with copper, but this reaction is not
as strong as the reaction with nitric acid only.
With citric acid and acetone no strong reaction occurs.
EXPERIMENT 90
---------------
Nitric acid, mixed with sulphuric acid is a strong oxidizer. It is capable
of oxidizing iodine to iodate.
EXPERIMENT 91
---------------
When bromate, manganese (II), citric acid and sulphuric acid are mixed at
certain propertions, then an oscillating reaction occurs, finally resulting
in an oily compound, which separates from the aqueous liquid.
EXPERIMENT 92
---------------
When bromate, manganese (II), malonic acid and sulphuric acid are mixed at
certain conditions, then a very convincing oscillating reaction occurs,
which persists for few minutes, going through a cycle many times, before
a final state is reached.
EXPERIMENT 93
---------------
Cr(III) can be reduced to Cr(II) by a zinc nail. On reoxidation to Cr(III)
a coordination complex appears to be created, both with sulfate and with
chloride.
EXPERIMENT 94
---------------
Chromium (III) can have many different colors, depending on how it is
created and with which it coordinates.
EXPERIMENT 95
---------------
When chromium (III) is created by reduction from dichromate with acidified
sulfite, then a green ion is formed. When acidified sulfite is added to
violet chromium (III), then the ions remain violet.
Apparently the way of creating chromium (III) determines its color (and
hence to what it is coordinated).
EXPERIMENT 96
---------------
When chromium (III) is created from dichromate, its color depends on the
reductor used and on the acid which is used for supporting the redox
reaction.
EXPERIMENT 97
---------------
Sodium dichromate dissolves in water very well, much better than potassium
dichromate. When it is reduced, then it is hard to crystallize a chrome
(III) salt or a mixed sodium chrome (III) salt.
EXPERIMENT 98
---------------
Chromium (III) apparently builds a coordination complex with hydroxyl amine,
but this complex does not simply form from chromium (III) salts and
hydroxyl amine. If chromium (III) is formed by means of reduction of
chromium (VI) in the presence of hydroxyl amine, then the complex is
formed. If hydroxyl amine is added to chromium (III) without redox reaction,
then another complex is created.
EXPERIMENT 99
---------------
Potassium tetraperoxochromate slowly dissolves in concentrated sulphuric
acid, it quickly dissolves (and decomposes) in dilute acid.
EXPERIMENT 100
---------------
Hexavalent chrome forms a stable volatile compound, when mixed with chloride
in strongly dehydrating conditions. The compound formed is called chromyl
chloride and its constitution is CrO2Cl2.
EXPERIMENT 101
---------------
When potassium dichromate is reduced by thiourea in acidic environments, then
a moss-green compound of chromium (III) is formed. When already existing
chrome (III) is added to a solution with thiourea, then the moss-green
compound is not formed.
EXPERIMENT 102
---------------
Chromium (III) builds a coordination complex with nitrite of a fairly
intense purple color.
EXPERIMENT 103
---------------
Chromium (III) builds a purple complex with EDTA, both when it is created
from dichromate and when it already exists and is brought in contact with
EDTA. When the pH is too low (or is this due to formation of a complex with
sulfate?), the formation of the complex does not occur.
EXPERIMENT 104
---------------
Bisulfite and sulfite form coordination complexes with chromium (III). The
exact behaviour strongly depends on the pH of the solution.
When the pH is raised with sulfite and then decreased again with sulphuric
acid, then the color does not revert to the original color of aqueous
chromium (III). Probably a new compound is found, which is inert and does
not fall apart quickly in acidic environments.
EXPERIMENT 105
---------------
When dichromate is brought in contact with peroxide, then after an initial
transient, a green variation of chromium (III) is produced. This compound,
however, slowly changes to a bluish/violet compound.
EXPERIMENT 106
---------------
When dichromate is reduced with metabisulfite in acidic environment, then
a chromium (III) compound is formed, which does not easily crystallize
from the liquid as chrome alum. The chromium (III) compound is green,
instead of violet.
EXPERIMENT 107
---------------
Dichromates are not capable of oxidizing nitrite in neutral environments.
When some acid is added, then the oxidation proceeds, but a fairly low
pH is needed for a fast and complete reaction.
EXPERIMENT 108
---------------
Dichromate is not capable of oxidizing formiate in reasonable time.
EXPERIMENT 109
---------------
Dichromate is capable of oxidizing tartaric acid and a colorless gas is
formed in this reaction (probably CO2). The liquid becomes purple/grey
(hard to describe color, depending on viewing illuminant).
The reaction product does not form a special complex in alkaline environment,
the familiar green color of chromium (III) in alkaline environments is
created. Addition of glycerol does not result in formation of a special
coordination complex.
When, however, dichromate is reduced by an excess amount of glycerol, then
a special coordinate complex appears to be formed, when the solution is
made alkaline. Even addition of acid does not destroy this complex.
EXPERIMENT 110
---------------
Dichromate is reduced by sulfite in neutral/slightly alkaline enviromments.
Under these conditions a jelly-like precipitate is formed, which is fairly
stable and does not dissolve immediately in dilute sulphuric acid. This
jelly-like precipitate is a chromium (III) compound.
The compound, however, does dissolve easily in strongly alkaline liquids.
The formation of this compound is not affected by the type of the cation
in the chromium-compound.
EXPERIMENT 111
---------------
Potassium dichromate dissolves in methanol, albeit not as well as in water.
Potassium chromate hardly dissolves in methanol. When ammonium thiocyanate
is added, then the liquid becomes deep yellow. Is this due to chromate, or
is this some reaction product from the thiocyanate?
EXPERIMENT 112
---------------
Chromium (III) is not reduced to chromium (II) by borohydride. Alkaline
chromium (VI) is only reduced slowly by borohydrode. On acidification the
reduction goes at once, but no further than the +3 oxidation state.
EXPERIMENT 113
---------------
Aniline, combined with acidified dichromate gives intensely colored compounds.
EXPERIMENT 114
---------------
Aniline gives colored compounds with chromium. The colors are remarkably
intense.
EXPERIMENT 115
---------------
Chromium (III) chloride initially gives a green solution in water, which on
standing turns violet/grey. The chromium/chloride complex slowly is changed to
plain aqueous chromium and free chloride ion. This takes a few days before
completion.
With nitrite ions, a purple complex is formed.
EXPERIMENT 116
---------------
Persulfate is not capable of oxidizing manganese to the (VII) state
in acidic environments.
EXPERIMENT 117
---------------
Potassium permanganate easily oxidizes oxalic acid. Succinic acid is not
oxidized easily.
EXPERIMENT 118
---------------
Manganese (II) ions apparently do not form coordination complexes with EDTA.
If they do so, then the coordination complex is (almost) colorless.
EXPERIMENT 119
---------------
Permanganate is a strong (and dangerous) oxidizer, when combined with
concentrated sulphuric acid. It is capable of lighting paper and acetone,
without the use of matches.
Permanganate, mixed with a mixture of nitric acid and sulphuric acid is
a strong oxidizer as well, but not as powerful as when mixed with
sulphuric acid only.
EXPERIMENT 120
---------------
Manganese builds a coordination complex with EDTA, which appears to be
pink. What oxidation state does the manganese have with this complex? It
appears to have oxidation state 2, unless EDTA is easily oxidized by
manganese, having a higher oxidation state.
EXPERIMENT 121
---------------
Manganese (II) gives an off-white precipitate with ferrocyanide and it gives
a dark brown precipitate with ferricyanide. The brown compound probably is
a manganese (IV) compound, formed through oxidation by ferricyanide.
EXPERIMENT 122
---------------
Periodate is capable of oxidizing manganese (II) to permanganate completely
in a short period of time. This is one of the rare examples of an oxidizer,
which is capable to oxidize manganese all up to the +7 oxidation state in
aqueous environments.
EXPERIMENT 123
---------------
Silver (I) gives a pale yellow precipitate with carbonates.
EXPERIMENT 124
---------------
Silver nitrite is only sparingly soluble in water. When dilute acid is
added, the compound is destroyed again.
EXPERIMENT 125
---------------
Silver (I) ions form a precipitate, both with ferrocyanide and with
ferricyanide. The precipitate with ferricyanide is decomposed by alkalies,
the precipitate with ferrocyanide is more stable. Both compounds are
attacked by thiosulfate, which complexes the silver and causes the
solid to dissolve again.
EXPERIMENT 126
---------------
Silver salts give a yellow precipitate with silicates. This precipitate
becomes white on addition of sulphuric acid. When a large quantity of
sodium hydroxide is added, then a dark, almost black, solid is created.
EXPERIMENT 127
---------------
Oxalic acid is supposed to react with sulfuric acid, forming carbon monoxide.
The experiment, described below, however, did not yield such results.
EXPERIMENT 128
---------------
Ethanol and acetic acid do not form an ester (ethylacetate) when simply
mixed with concentrated sulphuric acid. More extreme conditions are needed
for this reaction to occur.
The acid is diluted too much in order to give a strong reaction with
chlorate, combined with the reducing agent in the form of ethanol.
EXPERIMENT 129
---------------
When ethanol and acetone are mixed, together with sulphuric acid, then no
special visible reaction occurs. The compounds are bound to the acid. Their
smell hardly exists after mixing with the acid.
The mixture is not capable anymore of producing HCl from NaCl, nor does it
show a strong reaction with KMnO4 (as was expected, due to the presence of
concentrated H2SO4).
EXPERIMENT 130
---------------
MEK reacts with sulphuric acid. A quick reaction occurs when the liquids
are mixed and a lot of heat is produced. Further reaction takes a few days.
The second reaction stage results in formation of a oil-like product
(a polymerization product?).
EXPERIMENT 131
---------------
Ascorbic acid is oxidized in a strongly alkaline environment, probably by
oxygen from the air. The oxidation product can be oxidized further, but
this only occurs slowly, compared to the speed with which fresh ascorbic
acid can be oxidized.
EXPERIMENT 132
---------------
Bromine reacts with acetylene gas. The bromine disappears and a compound
is formed with a peculiar sweetish smell.
EXPERIMENT 133
---------------
Methanol reacts with nitrites in the presence of acid and of water. A
colorless gas is produced. Is this methyl nitrite? Without the water, or
without the acid, no reaction occurs.
EXPERIMENT 134
---------------
Ferricyanide is capable of oxidizing iodide to iodine, even in neutral
environments. The reaction, however does not appear to go to completion.
EXPERIMENT 135
---------------
Aluminium (III) does not form colored compounds with ferrocyanide nor with
ferricyanide. Manganese (II) reacts with both of them, but a colored
compound is formed with ferricyanide only.
EXPERIMENT 136
---------------
The ferric ammonium citrate complex is destroyed by acid. The green one
is destroyed instantaneously, the brown one slowly is decomposed.
The resulting ferric ions can be reduced to almost colorless ferrous ions.
EXPERIMENT 137
---------------
Ferric ions, bound to citrate, can coexist in solution with ferricyanide,
when the pH of the liquid is not too low. At lower pH the ferric citrate
complex is destroyed and the free ferric ions combine with the ferri-
cyanide ions.
EXPERIMENT 138
---------------
Ferrocyanide and ferricyanide decompose on heating with dilute sulphuric
acid. When the decomposition product of ferrocyanide is treated with
hydrogen peroxide, then it looks very much like the decomposition product
of ferricyanide.
EXPERIMENT 139
---------------
Iron (III) builds a coordination complex with phosphates.
EXPERIMENT 140
---------------
Ferrocyanide in acidic environments reacts with bromine in a very peculiar
way. An extremely dark compound is formed. This reaction does not occur
in neutral environments and this cannot be observed with ferricyanides.
What is the dark compound? Is it a coordination complex or a condensation
product of many ferric/ferrous ions, close to formation of solid particles?
EXPERIMENT 141
---------------
Ferrocyanide is oxidized quickly by nitrite in acidic environments. On
prolonged standing, a darker green/brown compound is formed.
EXPERIMENT 142
---------------
Ferric ions form a colorless complex with phosphate ions in acidic
environments. In the presence of chloride ions, a yellow coordination
complex is formed, which can exist, even in the presence of phosphate.
EXPERIMENT 143
---------------
Hydroxylamine is capable of reducing ferricyanide to ferrocyanide. On heating,
however, a yellow compound is formed, which apparently is not ferricyanide.
With thiocyanate a pale rose-purple solution is formed on standing. Probably
oxygen from the air also takes part in the reaction.
EXPERIMENT 144
---------------
Iron (III) forms a very dark brown/red coordination complex with nitrite,
both in water and in DMSO. On acidification, this complex decomposes, giving
a bright yellow solution with a slight green tinge.
EXPERIMENT 145
---------------
Nickel (II) gives a black precipitate when treated with hydroxide and
persulfate at the same time. It is expected that this is an higher
oxide of nickel (NiO2).
EXPERIMENT 146
---------------
Permanganate is not capable of oxidizing nickel (II) in an acidic
environment. In an alkaline environment it appears to be possible to
oxidize nickel (II) with permanganate.
EXPERIMENT 147
---------------
This experiment describes a qualitative method, useful for showing the
presence of minute quantities of manganese (II), which cannot be detected
by oxidation with H2O2 in alkaline environments anymore. Chloride ions
may not be present besides the manganese to be detected.
EXPERIMENT 148
---------------
Nickel forms colored coordination complexes with EDTA.
EXPERIMENT 149
---------------
Nickel (II) forms a coordination complex with bromide, but only in very
concentrated bromide solutions.
Such a concentrated bromide solution is oxidized by concentrated sulfuric
acid extremely rapidly.
EXPERIMENT 150
---------------
The nickel (II) salt of ferrocyanide is not soluble in water.
EXPERIMENT 151
---------------
When sodium sulfide and sodium nitrite are mixed as solids, or when mixed in
aqueous solution, no reaction occurs. Sulfide ion and nitrite ion can coexist
in solution.
When a very small amount of acid is added, a bright yellow/ochre solid compound
is formed, which slowly turns lighter. When more acid is added, then the solid
becomes almost white.
The very light yellow, almost white compound most likely is very finely divided
elemental sulphur. The much brighter yellow/ochre definitely is not sulphur,
its color is too strong and also differs quite a lot from the kind of yellow of
sulphur.
EXPERIMENT 152
---------------
Copper(II) can be reduced to the very peculiar compound CuH by hypophosphorous
acid, but only under very specific conditions. The compound CuH is quite
unstable and easily looses hydrogen.
In the presence of chloride ions, no CuH is formed, but CuCl is formed instead.
EXPERIMENT 153
---------------
Sodium chlorite and sodium nitrite do not react with each other in neutral
solution, but when acid is added, they react extremely violently, possibly
explosively.
EXPERIMENT 154
---------------
Ethylene glycol forms a nitrite ester quite easily. Most likely, the ester
formed is a di-ester, on both hydroxyl groups of the glycol.
EXPERIMENT 155
---------------
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 156
---------------
Thiourea is oxidized in acidic solution to formamidine disulfide, which exists
in solution as an acid salt. When a strong base is added, then the free base is
formed, but this at once decomposes. One of the decomposition products is
sulphur.
When excess oxidizer is used and the pH is increased strongly, then the sulphur
dissolves, giving rise to formation of polysulfides.
EXPERIMENT 157
---------------
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 158
---------------
Sulphuric acid and acetic anhydride react with each other. This reaction is
very violent. The final product is a very viscous colorless liquid. The main
constituent of this liquid is acetyl sulfate or acetyl bisulfate.
EXPERIMENT 159
---------------
Red phosphorus dissolves in concentrated sulphuric acid, when it is strongly
heated.
EXPERIMENT 160
---------------
A mix of finely powdered sodium hypophosphite and potassium bromate forms an
energetic mix which can easily be ignited.
EXPERIMENT 161
---------------
Selenium dissolves in very hot concentrated sulphuric acid, forming a dark
green liquid. On dilution, the red allotrope of selenium is precipitated.
EXPERIMENT 162
---------------
Chromium(III) oxide is extremely inert when it is calcined. It does not
dissolve in the common acids, nor in solutions of common bases. The solid,
however, can be oxidized by a solution of a bromate.
EXPERIMENT 163
---------------
Vanadium in oxidation state +5 is capable of oxidizing ethanol in acidic
solution, but this reaction is very very slow.
EXPERIMENT 164
---------------
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 165
---------------
When a solution of manganese(II)chloride in moderately concentrated
hydrochloric acid is electrolysed, then at the anode a remarkable very dark
compound is formed. The liquid remains clear, but it becomes very dark. This
must be a compound of manganese in higher than +2 oxidation state.
When a similar experiment is performed with manganese(II)sulfate in a 20%
solution of sulphuric acid, then a drk brown precipitate is formed at the
anode.
EXPERIMENT 166
---------------
Chlorite ion and nitrite ion react with each other in acidic medium, giving off
quite some heat, while this does not occur with chlorate and nitrite.
EXPERIMENT 167
---------------
Sodium dichromate anhydrous dissolves in methanol quite well, but does not
react with it. When a little concentrated sulphuric acid is added, then
suddenly a very violent reaction occurs.
With potassium dichromate, this violent reaction does not occur. The latter is
nearly insoluble in methanol and hence it hardly can react with it.
EXPERIMENT 168
---------------
The tetrathionate ion is much more stable than the thiosulfate ion in acidic
solution.
EXPERIMENT 169
---------------
Calcium iodate is very sparingly soluble in water, but it can form strongly
oversaturated solutions and may take a long time to crystallize.
Calcium iodate also is quite stable, it must be heated strongly in order to
decompose it.
EXPERIMENT 170
---------------
Nitrite ion reacts very easily with ethanol in acidified solution to form ethyl
nitrite. The ethyl nitrite easily escapes as gas from the liquid (it has a
boiling point of 17 C). The gas can be ignited and burns with a grey flame.
EXPERIMENT 171
---------------
Chlorite ion and chlorine dioxide are sluggish oxidizers when in aqueous
solution, even in the presence of quite some acid. Bromide ion only is oxiduzed
very slowly and only partially.
EXPERIMENT 172
---------------
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 173
---------------
A solution of tetrathionate reacts with nitrite in acidic solution. A green
compound is formed, which however is unstable and after a few minutes, the
solution decomposes. It becomes turbid and light yellow. Most likely the yellow
material is finely divided sulphur.
EXPERIMENT 174
---------------
Cyanate ion forms complexes with many metal ions. These complexes have a strong
color and are not stable in acidic solution.
EXPERIMENT 175
---------------
The combination of acetyl and sulfate, either directly, or derived from other
compounds reacts extremely energetically with water. It is remarkable that it
is this specific combination of three entities which gives extremely violent
reactions. This effect is demonstrated with different chemicals in different
combinations.
EXPERIMENT 176
---------------
When thiosulfate ion and nitrite ion are brought together in solution, then
nothing happens. When the solution is acidified, then a remarkable reaction
occurs. The liquid then quickly turns dark brown and remains clear. Immediately
after that, a colorless gas is produced and the color becomes lighter. The
color goes from dark brown through brown/orange and yellow to lime green. The
liquid remains clear and lime green for a few minutes and then it slowly
becomes turbid.
EXPERIMENT 177
---------------
Ethylacetate is in equilibrium with ethanol and acetic acid, even in dilute
aqueous solution with some free acid in it. Usually, making esters requires
rather forcing conditions, like mixing an alcohol and an organic acid and
adding this mix to concentrated sulphuric acid and then heating the mix. This
experiment nicely demonstrates that there is an equilibrium, also in water.
EXPERIMENT 178
---------------
An acidified solution of potassium bromate quickly oxidises solid potassium
nitrite to potassium nitrate, the bromate being converted to bromine.
EXPERIMENT 179
---------------
Periodate is capable of oxidizing nitrite ion but only very slowly.
End of results for 'sulphuric acid'