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Experiments for 'sodium hydroxide'
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Results for 'sodium hydroxide':
EXPERIMENT 1 --------------- Thiocyanate reacts with nitrogen dioxide to form a red/brown compound. It does not react with nitrogen monoxide. When a reaction occurs with NO2, a white fume is produced.
EXPERIMENT 2 --------------- Hydroxyl amine reacts with acetone, releasing (some) heat. After this reaction, the resulting compound is shown to still be a relatively strongly reducing agent in alkaline solution.
EXPERIMENT 3 --------------- Hydrogen cyanide (or cyanide salt) slowly changes to a dark brown/black compound, when it is allowed to stand. At least this happens in strongly acidic media.
EXPERIMENT 4 --------------- Nitromethane gives a dark red/brown liquid in combination with aqueous sodium hydroxide. This most likely is a polymeric species.
EXPERIMENT 5 --------------- Vanadium (V) builds different kinds of poly-vanadates, with colors ranging from colorless to deep orange/red.
EXPERIMENT 6 --------------- 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 7 --------------- 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 8 --------------- 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 9 --------------- Vanadium (IV) does not build complexes with EDTA in acidic environments.
EXPERIMENT 10 --------------- 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 11 --------------- 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 12 --------------- 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 13 --------------- Vanadium (V) compounds can coexist with ferricyanide in solution. Reduction of either one of them results in formation of a precipitate.
EXPERIMENT 14 --------------- Vanadyl gives diverse complexes with citrate, the color of these complexes strongly depends on the pH of the solution.
EXPERIMENT 15 --------------- 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 16 --------------- 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 17 --------------- 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 18 --------------- 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 19 --------------- 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 20 --------------- 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 21 --------------- Vanadium (V) is capable of forming many peroxo compounds, whose appearance strongly depends on pH.
EXPERIMENT 22 --------------- 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 23 --------------- Vitamin C is a strong reductor in alkaline environments. Copper (II) is reduced to copper (I).
EXPERIMENT 24 --------------- Hydroquinone is capable of reducing copper (II) to copper (I) in alkaline environments. The copper is not reduced to its metallic form.
EXPERIMENT 25 --------------- Copper hydroxide is not capable of oxidizing methanol.
EXPERIMENT 26 --------------- Formaldehyde is not capable of reducing Fehlings reagent within a few minutes at temperatures of appr. 60 C.
EXPERIMENT 27 --------------- Metol is capable of reducing copper (II) to copper (I) in alkaline environments.
EXPERIMENT 28 --------------- Copper (II) builds a coordination complex with glucose in alkaline environments. On heating, the glucose is oxidized by the copper (II) and orange/red Cu2O precipitates.
EXPERIMENT 29 --------------- Copper gives a coordination complex with catechol, but only in alkaline environments. This complex is easily oxidized by oxygen from air. Iron also forms a complex in acidic media, probably by a combined red/coordination reaction.
EXPERIMENT 30 --------------- Copper (II) gives a coordination complex with ascorbic acid in neutral or slightly acidic environments. In alkaline environments copper (II) is reduced rapidly by ascorbic acid / ascorbate.
EXPERIMENT 31 --------------- Copper builds a complex with urea, which has a pale purple color (or is this due to contamination of the urea with traces of biuret?). The copper, bound to urea, does not build the intense blue cuprammine complex with ammonia.
EXPERIMENT 32 --------------- EDTA builds a coordination complex with copper (II). This complex has a color, resembling the color of simple hydrated copper (II), but it is much more intense and it has a slightly more cyan-like color. This complex is not stable in strongly alkaline environments.
EXPERIMENT 33 --------------- When copper (II) is reduced by dithionite in neutral environments, then a dark red/brown precipitate is formed (metallic copper??). When reduced in alkaline environments, then hydrous copper (I) oxide is formed.
EXPERIMENT 34 --------------- 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 35 --------------- Copper (II) reacts with thiourea, forming a pale/yellow precipitate, looking like sulphur. This precipitate, however, is not sulphur (what is it???).
EXPERIMENT 36 --------------- In alkaline environments, copper (II) shows remarkable behavior, when brought in contact with strong oxidizers or reductors.
EXPERIMENT 37 --------------- Hydroxyl amine sulfate (containing protonated hydroxyl amine) is not capable of reducing copper (II). When the liquid becomes basic (releasing free hydroxyl amine), then the copper (II) is reduced to copper (I).
EXPERIMENT 38 --------------- Copper builds a remarkable complex with ascorbic acid and is easily reduced by ascorbic acid in alkaline environments. Copper (II) builds a brown compound with hydrogen peroxide in alkaline environments.
EXPERIMENT 39 --------------- Copper (II) does not form a coordination complex with phosphates and/or phosphoric acid.
EXPERIMENT 40 --------------- Copper (II) is reduced by hydroxyl amine very quickly in alkaline environments. Yellow copper (I) hydroxide/oxide is formed.
EXPERIMENT 41 --------------- Copper (II) forms a coordination compound with ethyl acetate, which has reacted with hydroxyl amine.
EXPERIMENT 42 --------------- Copper hydroxide easily looses water, when it is heated, even if it is completely covered with water.
EXPERIMENT 43 --------------- Mercury (II) ions produce a bright orange colored precipitate with iodide.
EXPERIMENT 44 --------------- Mercury (II) salts give an oxide/hydroxide, which does not dissolve in large excess amounts of alkaline solutions. Ammonia does not dissolve the precipitate of mercury (II) oxide/hydroxide.
EXPERIMENT 45 --------------- This is a very nice experiment, involving beautifully coloured compounds, but it is a hazardous experiment as well, due to the use of mercury (II) compounds. Mercury (II) builds a complex with excess iodide, [HgI4]2-, which gives a beautiful bright yellow precipitate with Ag+ and a beautiful bright brick- red precipitate with Cu+.
EXPERIMENT 46 --------------- Titanium dissolves in dilute hydrochloric acid with great difficulty. When hydrofluoric acid is present as well, then the metal dissolves easily. A tinanium (III) fluoro complex is formed.
EXPERIMENT 47 --------------- Titanium slowly dissolves in concentrated hydrochloric acid, forming deep blue/violet titanium (III) ions. On addition of hydrogen peroxide these are oxidized to titanium (IV), which in turn forms a deep red coordination complex with hydrogen peroxide. The deep red coordination complex is only stable in acidic to neutral media. It also is easily reduced by nitrite. It is not affected strongly by persulfate. With fluoride, a light yellow compound is formed, but the formation of that may also be due to rise of pH.
EXPERIMENT 48 --------------- Cobalt (II) forms a coordination complex with nitrous oxide, which easily decomposes again. On addition of alkali, the cobalt is oxidized and appears to build a cobalt-compound of an higher oxidation state.
EXPERIMENT 49 --------------- Cobalt gives a green coordination complex with tartrates, when oxidized to the +3 state.
EXPERIMENT 50 --------------- 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 51 --------------- Cobalt (II) salts give a blue/green precipitate when dilute ammonia is added. This precpitate is fairly stable towards air. When more concentrated ammonia is used, then a dark brown compound is formed, but this compound is formed by contact with air. On addition of hydrogen peroxide also a very dark brown compound is formed. When the pH is increased strongly, then the blue precipitate is not stable anymore, instead a dark bright blue compound is formed, which, however, quickly turns pink. When a large amount of ammonia is replaced by ammonium, then the blue precipitate is not formed anymore, but a coordination complex is formed, which is very easily oxidized by oxygen from the air.
EXPERIMENT 52 --------------- 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 53 --------------- Acetone can be mixed with water in any ratio, but when sodium hydroxide is added, then the liquids are not miscible in any ratio anymore. Sulphur reacts with acetone in the presence of sodium hydroxide. Sulfide does not show such a reaction.
EXPERIMENT 54 --------------- 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 55 --------------- In strongly alkaline environments, molybdates are not as easily reduced as in neutral or acidic environments.
EXPERIMENT 56 --------------- 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 57 --------------- 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 58 --------------- Molybdate forms strongly colored, but unstable, complexes with hydrogen peroxide.
EXPERIMENT 59 --------------- 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 60 --------------- 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 61 --------------- Silver bromide is reduced by metol in alkaline medium.
EXPERIMENT 62 --------------- Diverse phenol-derivatives, can be oxidized easily by bromine, yielding intensely colored oxidation products.
EXPERIMENT 63 --------------- Hydroquinone is a very strong reductor in alkaline environments. Oxygen from the air is readily absorbed by an alkaline solution of hydroquinone. Sulfite, however, makes an alkaline solution of hydroquinone much more stable, because of formation of special hydroquinone/sulfite compounds.
EXPERIMENT 64 --------------- Hydroquinone is not oxidized to the dark brown product by hydrogen peroxide as it is done by oxygen from the air in alkaline environments.
EXPERIMENT 65 --------------- Hydroquinone is readily oxidized by ferricyanide, even in the presence of sulfite, when in alkaline environments.
EXPERIMENT 66 --------------- Metol is easily oxidized by oxygen from the air, when dissolved in alkaline media. When sulfite is present, however, oxidation does only occur at a low rate.
EXPERIMENT 67 --------------- Silver (I) is reduced to metallic silver by metol. This metallic silver is easily oxidized by peroxosulfate. Insoluble silver (I) compounds dissolve in thiosulfate solutions (principle of photography fixer) while metallic silver is not affected. When a mild oxidizer is added, the metallic silver also dissolves (principle of photography reducer, Farmer's reducer).
EXPERIMENT 68 --------------- Photography developers, based on phenol-like structures, are easily oxidized by air in alkaline environments and the oxidation products are such, that a reverse process does not occur anymore (probably the oxidation products are large polymerized species).
EXPERIMENT 69 --------------- Pyrogallol does not dissolve in trichloroethene very well, but some of it does dissolve.
EXPERIMENT 70 --------------- Pyrogallol is quickly oxidized in alkaline environments by oxygen from the air. The more alkaline, the faster this reaction proceeds. The black oxidation products are affected by acid, but the pyrogallol is not recovered by the acid.
EXPERIMENT 71 --------------- P-aminophenol is quickly oxidized by oxygen from air in alkaline solution. When acidified, the oxidation product becomes much lighter, but the original compound is not restored again.
EXPERIMENT 72 --------------- Phenidone is oxidized by air, but is much less susceptible to oxidation than developers, such as hydroquinone, pyrogallol.
EXPERIMENT 73 --------------- Benzotriazole is not oxidized by air. Apparently it forms a coordination complex with chromium (III).
EXPERIMENT 74 --------------- It appears that copper (II) ions catalyse the oxidation of pyrogallol by hydrogen peroxide.
EXPERIMENT 75 --------------- Copper (II) apparently catalyses the oxidation of pyrogallol by oxygen from the air.
EXPERIMENT 76 --------------- Pyrogallol gives rise to many colored products on oxidation and coordination. More investigation is needed in order to get more insight in all these colors and the conditions under which they are formed.
EXPERIMENT 77 --------------- Nitrite reacts with p-aminophenol violently in alkaline environments.
EXPERIMENT 78 --------------- Catechol, resorcinol and hydroquinone all are dihydroxy benzenes. When an ortho-pair (1,2-pair) or a para-pair (1,4-pair) is present, then the compound is easily oxidized by air in alkaline environment. When a meta-pair (1,3-pair) is present, such a reaction does not occur.
EXPERIMENT 79 --------------- 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 80 --------------- 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 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 --------------- Tungstate ions, when reduced, produce a deep blue color. Tungstate is a weak oxidizer.
EXPERIMENT 83 --------------- Persulfate decomposes in strongly alkaline environments.
EXPERIMENT 84 --------------- Cadmium selenide reacts vigorously with nitric acid, producing nitrous fumes and a yellow/orange solid, which is filled with many small gas bubbles and hence remains floating on the liquid. Cadmium sulfide gives a similar reaction, but now a pale yellow solid is formed. This yellow solid is sulphur.
EXPERIMENT 85 --------------- Tannine (a polyphenolic compound of large molecular weight of indeterminate composition) reacts with many metal ions, forming highly coloured complexes. It also shows some other reactions. The exact type of reactions is not always clear. The tannine, used in these experiments, was brown. It's intended use is as an additive for making wine.
EXPERIMENT 86 --------------- Rhenium is oxidized easily by nitric acid. The oxidation product is a color- less compound, soluble in water (according to literature it is perrhenic acid, HReO4). Perrhenic acid is not a really strong oxidizer. It can be reduced by zinc, but addition of sodium sulfite does not result in formation of the same compound. Hydrogen peroxide is capable of oxidizing back to perrhenic acid, but some light yellow compound remains. What is it?
EXPERIMENT 87 --------------- Rhenium, when dissolved in nitric acid, gives colorless perrhenate ions, [ReO4]-. With zinc, in the presence of hydrochloric acid of sufficient concentration, this can be reduced to a yellow/green species. With cyanide, in alkaline environment this forms a brown and clear solution. The yellow/ green species may be [ReCl6]2-, which according to literature is green. With cyanide, a complex may be formed.
EXPERIMENT 88 --------------- Rhenium can be oxidized to colorless perrhenate [ReO4]-, with nitric acid. With zinc it can be reduced to a yellow/green species in the presence of hydrochloric acid at sufficient concentration. This species apparently is not reduced any further with borohydride in alkaline environments. In acidic environments, a dark brown/black compound can be formed easily, due to reduction of thiosulfate to sulfide by the borohydride. The sulfide forms a dark compound with rhenium. With sulfite, perrhenate nor the yellow/green compound can be reduced to a lower oxidation state.
EXPERIMENT 89 --------------- Chromium (III) has many different colors, depending on coordinated ligands.
EXPERIMENT 90 --------------- Chromium (III) can be converted to chromium (VI) in strongly alkaline environments.
EXPERIMENT 91 --------------- Oxidation of chromium (III) to chromium (VI).
EXPERIMENT 92 --------------- Chromium (III) can be oxidized to chromium (VI) by persulfate in alkaline environments.
EXPERIMENT 93 --------------- Bleach is capable of oxidizing chromium (III) to its hexavalent state, but this is not accomplished easily and completely.
EXPERIMENT 94 --------------- EDTA builds pink complexes with chromium (III). This complex is destroyed in strongly alkaline environments.
EXPERIMENT 95 --------------- Chromium (III) is oxidized to dichromate (chrome (VI)) by persulfate. This reaction is catalyzed by silver (I).
EXPERIMENT 96 --------------- Basic chromium (VI), chromate, is not capable of oxidizing ascorbate. On acidification, immediate oxidation occurs and a coordination complex is formed.
EXPERIMENT 97 --------------- Chromate is reduced by dithionite in strongly alkaline solution, but this reaction proceeds slowly.
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 --------------- 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 100 --------------- Chromium (III) forms a lavender precipitate, when combined with hydroxyl amine in alkaline environments. This compound does not dissolve in strongly alkaline environments.
EXPERIMENT 101 --------------- 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 102 --------------- 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 103 --------------- Dichromate reacts with hydrogen peroxide, yielding chromium (III) as the final product, in acidic environments. In alkaline environments, chromium (III) yields chromate with hydrogen peroxide.
EXPERIMENT 104 --------------- 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 105 --------------- Hydroxyl amine gives a brown coordination complex when it reduces hexavalent chromium to trivalent chromium in alkaline environments. This coordination complex is really due to the hydroxyl amine. When other reducing agents are used in the presence of ammonia in alkaline environments, then no similar reaction product can be obtained.
EXPERIMENT 106 --------------- Aniline, combined with acidified dichromate gives intensely colored compounds.
EXPERIMENT 107 --------------- Persulfate is not capable of oxidizing manganese to the (VII) state in acidic environments.
EXPERIMENT 108 --------------- Permanganate is capable of oxidizing thiocyanate in acidic environments: The result is a pink solution, more intensely colored than manganese (II) ions (which are almost colorless).
EXPERIMENT 109 --------------- Manganese (II) ions apparently do not form coordination complexes with EDTA. If they do so, then the coordination complex is (almost) colorless.
EXPERIMENT 110 --------------- 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 111 --------------- Manganese (II) forms a white precipitate with bicarbonate, while slowly developing a gas (probably this is CO2). This precipitate is not quickly oxidized by oxygen from the air. When the precipitate is made more alkaline by adding hydroxide, then it is oxidized fairly quickly. Addition of hydrogen peroxide causes immediate oxidation of the alkaline precipitate.
EXPERIMENT 112 --------------- Sulfide is capable of forming a brightly coloured compound with antimony (III) in a strongly acidic environment. The sulfide is not destroyed by strong acid and is not converted to hydrogen sulfide gas.
EXPERIMENT 113 --------------- Antimony sesquioxide does not dissolve in a concentrated solution of NaOH nor does it react with sulfide or one of the polysulfides in strongly alkaline environments.
EXPERIMENT 114 --------------- Silver (I) is not reduced by hydroxyl amine in neutral environments. When made alkaline, it is reduced to metallic silver immediately.
EXPERIMENT 115 --------------- Silver chloride and silver oxide dissolve in a solution of sodium thiosulfate. The reaction is not very fast.
EXPERIMENT 116 --------------- 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 117 --------------- 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 118 --------------- Silver (I) ions, when treated with hydroxide give brown silver (I) oxide. When hydrogen peroxide is added, then that is decomposed and the precipitate of oxide does not change noticeably. When, however, hydrogen peroxide is first mixed with a solution of a silver (I) salt and then the hydroxide is added, then a black precipitate is formed. Probably this is finely divided metallic silver.
EXPERIMENT 119 --------------- This experiment is performed in order to determine, whether iodoform (CHI3) shows a reaction, similar to chloroform, when treated with acetone in a strongly alkaline environment. The result of this experiments suggests that indeed a similar reaction occurs, resulting in the formation of a compound with a sweetish mint-like odour.
EXPERIMENT 120 --------------- Acetone reacts with sulphur in strongly alkaline environments. What products are formed? A similar reaction is observed between methyl ethyl ketone and sulphur.
EXPERIMENT 121 --------------- MEK can be oxidized by potassium permanganate in alkaline environments (or is this due to some impurities in the MEK?).
EXPERIMENT 122 --------------- Trichloro ethene reacts with acetone, forming a brown substance, but only when in a strongly alkaline environment. The exact conditions, under which this brown substance is formed must be further investigated.
EXPERIMENT 123 --------------- 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 124 --------------- Thymol reacts with chloroform and/or sodium hydroxide when heated. A yellow/ green compound is formed. What is this compound?
EXPERIMENT 125 --------------- Lead builds a yellow precipitate with hydroxide and peroxosulfate. This probably is an oxidation product of lead (II).
EXPERIMENT 126 --------------- Lead hydroxide is oxidized by hydrogen peroxide. The resulting compound does not dissolve in dilute nitric acid.
EXPERIMENT 127 --------------- Lead (II) salts give a yellow precipitate of lead chromate with dichromates. When this precipitate is made alkaline, then it turns orange.
EXPERIMENT 128 --------------- The blue precipitate, formed when ferrocyanide and ferric ions act upon each other is not stable in alkaline environments.
EXPERIMENT 129 --------------- Bleach is not capable of oxidizing ferric hydroxide to the hexavalent ferrate (at least not at 60 C within several minutes).
EXPERIMENT 130 --------------- Ferrous ions give a yellow coordination complex with oxalate. The normal color of ferrous ions is pale green. Ferric ions give a green coordination complex with oxalate. The normal color of ferric ions is yellow/brown. The ferric complex is only formed if the environment is not too acidic.
EXPERIMENT 131 --------------- The experiment described below suggests the formation of a coordination complex between iron and ascorbate. The presence of the ascorbate induces a completely different behavior of ferric/ferrous ions in alkaline environments.
EXPERIMENT 132 --------------- Ferric ions apparently form a coordination complex with glucose in alkaline environments. Normally ferric ions give a brown precipitate in strong alkaline liquids, with glucose the liquid remains clear.
EXPERIMENT 133 --------------- Ferric ions form coordination complexes with citrates and oxalates. These coordination complex have completely different properties than free ferric ions.
EXPERIMENT 134 --------------- When concentrated hydrochloric acid is added to a concentrated solution of potassium ferrocyanide, then a white precipitate is formed (probably this is KCl). The liquid slowly turns blue, but this is not due to formation of the well known prussian blue or a similar compound.
EXPERIMENT 135 --------------- Dithionite is not capable of reducing ferric oxide/hydroxide to an iron (II) compound in alkaline environments.
EXPERIMENT 136 --------------- Ferrocyanide and ferricyanide react with hydroxyl amine in an unexpected way. The ferri complex first decolorizes, but then a new colored compound is formed. The ferro complex shows this behaviour immediately.
EXPERIMENT 137 --------------- When an acidified solution of ferric chloride is mixed with a solution of hydroxyl amine sulfate, then an almost colorless compound is formed, but this compound does not seem to be an iron (II) compound.
EXPERIMENT 138 --------------- Hydroxyl amine reacts with ferrocyanides, forming a dark compound. Is the ferrocyanide oxidized by the hydroxyl amine? This reaction occurs in neutral environments, with the hydroxyl amine bound in a hydroxyl ammonium salt.
EXPERIMENT 139 --------------- Potassium ferrocyanide reacts with concentrated nitric acid. The compound which is formed is dark brown/green. What is this compound? Is the dark brown/green color due to formation of a Fe(NO)+ complex, well known from the brown-ring test for nitrates?
EXPERIMENT 140 --------------- Iron (III) builds a coordination complex with phosphates.
EXPERIMENT 141 --------------- 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 142 --------------- Ferrous ions react with hydroxide, forming a light bluish/grey precipitate. This precipitate, however, quickly turns brown.
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 --------------- A precipitate of nickel hydroxide is oxidized by persulfate to a black compound (probably NiO2).
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 --------------- Hydrogen peroxide probably serves as a reductor for an higher oxide of nickel.
EXPERIMENT 147 --------------- 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 148 --------------- Nickel does not appear to build coordination complexes with thiocyanate, not even if acetone is added (in contrast to cobalt). Ni(OH)2 is oxidized to a dark compound by persulfate, even in the presence of a reducing agent like acetone.
EXPERIMENT 149 --------------- Nickel (II) does not form a coordination complex with ascorbic acid, not in neutral or slightly acidic environments, nor in alkaline environments.
EXPERIMENT 150 --------------- Nickel (II) builds a stable complex with EDTA. Once this complex is formed, it is not precipitated with NaOH and persulfate does not oxidize nickel (II).
EXPERIMENT 151 --------------- Nickel hydroxide can be oxidized by persulfate to a higher hydrous oxide (nickel (III) and/or nickel (IV) oxide), but nickel carbonate is not oxidized. The carbonate can be oxidized, however, when hydroxide is added to the solution.
EXPERIMENT 152 --------------- 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 153 --------------- Nickel forms colored coordination complexes with EDTA.
EXPERIMENT 154 --------------- Nickel (II) forms a complex with citrate. In a strongly alkaline environment the nickel (II) does not precipitate. With just a small amount of ferric ions present in the liquid, the complete liquid solidifies to a gelatin- like constitution. When the same experiment is done, without the nickel (II) present, no solidification is observed.
EXPERIMENT 155 --------------- Nickel in nickel (II) hydroxide is oxidized to a higher oxidation state by hypochlorites, but not by chlorates. The oxidation product is reduced by hydrogen peroxide and ammonia. Heating of the oxidation product makes it more resistant to reduction and to breakdown by acids.
EXPERIMENT 156 --------------- When compounds of manganese(IV) or manganese(VII) are added to hydrochloric acid, then chlorine gas is produced and the solution becomes very dark brown/green. Only after a long time of heating, all dark brown/green material is gone and what remains is a pale solution, containing manganese(II) ions.
In this series of experiments it was attempted to go the other way around. Is it possible to go from almost colorless manganese(II) to the dark colored compounds of manganese(III) or manganese(IV). This was done by adding chlorine to solutions of manganese(II) salts in concentrated hydrochloric acid.
While doing so, an interesting observation was made. The dark colored compound indeed can be made from manganese(II) in concentrated hydrochloric acid, but only from hypochlorite and not from chlorine.
When calciumhypochlorite is added to hydrochloric acid, then chlorine is formed vigorously, and the solution becomes green and clear.
It seems, however, that even in concentrated hydrochloric acid some of the hypochlorite is not decomposed at once, but remains in solution as yellow/green hypochlorous acid.
A freshly prepared solution, made from a pinch of calcium hypochlorite and concentrated hydrochloric acid, reacts differently than a saturated solution of chlorine in concentrated hydrochloric acid. This is shown with manganese(II) ions in hydrochloric acid.
EXPERIMENT 157 --------------- 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 158 --------------- Nickel(II) ion is reduced in slightly alkaline environment by borohydride ion, but only with difficulty, when the mix is heated.
EXPERIMENT 159 --------------- Iodine does not react with nitrite in methanolic solution. Iodine does react with hydroxide in methanolic solution, a very light yellow compound is formed. On acidification this gives iodine again. Iodine does react with red phosphorous in methanolic solution, but the reaction is slow.
EXPERIMENT 160 --------------- Arsenate ion and arsenic acid cannot easily be reduced to the element. Reduction to trivalent arsenic, however, can easily be accomplished with iodide.
EXPERIMENT 161 --------------- 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 162 --------------- Lead(II) hydroxide is easily converted to lead(II) oxide by simple boiling. The lead(II) oxide appears as nice glittering gold/yellow crystals.
EXPERIMENT 163 --------------- White phosphorus reacts with hot solutions of sodium hydroxide and gaseous phosphine and diphosphine are produced. The diphosphine spontaneously combusts in air, the phosphine does not. The diphosphine is very unstable and within a few minutes it reacts and only phosphine is left.
REMARK: THIS IS A VERY DANGEROUS EXPERIMENT. WHEN NOT CARRIED OUT WITH SUFFICIENT PRECAUTIONS. KNOW WHAT YOU ARE DOING!!
EXPERIMENT 164 --------------- Both oxone, active ion is HSO5(-), and peroxodisulfate, active ion is S2O8(2-), produce a black precipitate when added to nickel(II) ions at high pH. Hydrogen peroxide, on the other hand, only produces green nickel(II) hydroxide, and if the black precipitate is present, it is destroyed by hydrogen peroxide, with formation of oxygen and green nickel(II) hydroxide.
EXPERIMENT 165 --------------- When a solution of copper sulfate is added to a solution of hydroxyl ammonium chloride in dilute solution of NaOH, then a dirty green precipitate is formed. At some places the precipitate becomes yellow. When the liquid is shaken, then all of the precipitate dissolves and a colorless liquid is obtained. On standing, a thin layer of solid material is formed on the surface of the liquid. This layer has a dirty green color.
Hydroxyl amine reduces copper(II) at high pH and a colorless complex of copper(I) is formed, which at really high pH becomes unstable with formation of hydrous copper(I) oxide.
End of results for 'sodium hydroxide'
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