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Experiments for 'S'
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Results for 'S':
EXPERIMENT 1 --------------- 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 2 --------------- The hexanitrite cobaltate (III) ion is strongly affected by sulfide. A black compound is formed. On acidification of this, remarkably, no hydrogen sulfide is formed. Probably the black compound is a compound containing sulfide and nitrite in a single compound, which on acidification results in oxidation of the sulfide.
EXPERIMENT 3 --------------- Ferrous sulfide is a black precipitate, which easily dissolves in acid.
EXPERIMENT 4 --------------- Iron (III) gives a precipitate with S2-, but a redox reaction, resulting in the formation of sulphur also appears to occur.
EXPERIMENT 5 --------------- Thiosulfate gives a purple coordination complex with iron (III). This complex, however, is not stable. With iron (II) no complex is formed. Iron (III) is reduced by thiosulfate after the initial formation of the purple coordination complex. This is shown by adding ferrocyanide, which does not result in formation of an intense dark blue precipitate.
EXPERIMENT 6 --------------- Ferric ions form a coordination complex with sulfite.
EXPERIMENT 7 --------------- This experiment shows two things: 1) Permanganate can be reduced by metabisulfite, but the reduction does not proceed instantaneously when no additional acid is used. 2) Manganese sulfide is a dirty pink substance (color of flesh).
EXPERIMENT 8 --------------- 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 9 --------------- Sulphur dissolves in a solution of a sulfide. Polysulfides are formed.
EXPERIMENT 10 --------------- Sulfide gives precipitates with some metals, which do not dissolve in strong acids. These sulfides, however, can easily be dissolved, when an oxidizing agent is used. Sulfide is easily oxidized by moderately strong oxidizers.
EXPERIMENT 11 --------------- 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 12 --------------- This sequence of experiments shows that sulfite is capable of reducing silver (I), copper (II) and iron (III), but that these reactions all show their own peculiarities. Sulphur in the +4 oxidation state is a mild reductant.
EXPERIMENT 13 --------------- Sodium sulfide is oxidized by acidic hydrogen peroxide with extreme violence.
EXPERIMENT 14 --------------- Iodide ion and sulphur dioxide form a deep orange/yellow complex at high concentration. At somewhat lower concentration this complex looks deep yellow. The complex formed in this experiment is {I.nSO2]-.
EXPERIMENT 15 --------------- Thionyl chloride quickly hydrolyses in the presence of water.
EXPERIMENT 16 --------------- Iodide ion reacts with thionyl chloride, most likely giving iodine, and some sulphur(II) species. Potassium bromide does not dissolve in thionyl chloride (at least, not visibly). No reaction occurs.
EXPERIMENT 17 --------------- Potassium dichromate is sparingly soluble in thionyl chloride, giving an intensely colored red/orange/brown solution, which on addition to water at once becomes green with a blue hue. Potassium chromate does not dissolve in thionyl chloride. The solid changes color from yellow to yellow/orange, and the solution becomes slightly colored, but this faint reaction may be due to minor impurities in the potassium chromate or thionyl chloride. If any potassium chromate dissolves, then it is a very small amount.
EXPERIMENT 18 --------------- 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 19 --------------- Niobium pentachloride is soluble in thionyl chloride, but not very well. Also, such a solution becomes turbid.
EXPERIMENT 20 --------------- Acetone reacts with sulphur in strongly alkaline environments. What products are formed? A similar reaction is observed between methyl ethyl ketone and sulphur.
EXPERIMENT 21 --------------- Silver is coordinated by thiosulfate. The silver-thiosulfate complex does not show any of the reactions of free aqueous silver (I).
EXPERIMENT 22 --------------- Silver chloride and silver oxide dissolve in a solution of sodium thiosulfate. The reaction is not very fast.
EXPERIMENT 23 --------------- 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 24 --------------- Silver (I) ions give a dark brown precipitate with sulfide.
EXPERIMENT 25 --------------- Persulfate decomposes in strongly alkaline environments.
EXPERIMENT 26 --------------- 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 27 --------------- Nitric acid, mixed with sulphuric acid is a strong oxidizer. It is capable of oxidizing iodine to iodate.
EXPERIMENT 28 --------------- 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 29 --------------- Cadmium ions give a precipitate with sulfide at very low concentration of free sulfide ions. Only at very low pH, cadmium ions and hydrogen sulfide can coexist in solution at appreciable concentration. A very similar effect can be seen with combinations of cadmium and selenide.
EXPERIMENT 30 --------------- Sulfide reacts with metavanadates, resulting in the formation of a dark brown/greenish compound.
EXPERIMENT 31 --------------- 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 32 --------------- 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 33 --------------- Chromium (III) can be oxidized to chromium (VI) by persulfate in alkaline environments.
EXPERIMENT 34 --------------- Chromium (III) is oxidized to dichromate (chrome (VI)) by persulfate. This reaction is catalyzed by silver (I).
EXPERIMENT 35 --------------- When dichromate is added to sulfide, then a transient highly coloured compound is formed, immediately followed by reduction to green chromium (III) in alkaline environment.
EXPERIMENT 36 --------------- Potassium chlorate is able to liberate bromine from a bromide. Reaction with sodium sulfide of the bromine shows formation of fumes/smoke.
EXPERIMENT 37 --------------- When potassium bromate and sulphur are mixed, then a very dangerous mixture is created. This mixture, when ignited, produces an intensely bright flame.
EXPERIMENT 38 --------------- 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 39 --------------- Potassium chlorate and sulphur form a potentially explosive mixture, which is quite sensitive to shock.
EXPERIMENT 40 --------------- Bismuth forms a yellow complex with thiosulfate. In the presence of thiosulfate, it still forms a deep orange complex with iodide, just as without thiosulfate.
EXPERIMENT 41 --------------- 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 42 --------------- 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 43 --------------- Palladium (II) is not easily reduced by mild reducing agents. Only very strong reductors are capable of reducing this to metallic palladium. Strong oxidizers probably are capable of oxidizing palladium (II) to a higher oxidation state, but if this is true, then the higher oxidation state has almost the same color.
Sulfite, instead of reducing palladium to the metallic state, appears to form a brightly colored coordination complex in acidic environments.
EXPERIMENT 44 --------------- Acetyl chloride is capable of dehydrating copper(II) chloride, and it even is capable of replacing sulfate ion by chloride, itself being converted to acetyl sulfate.
EXPERIMENT 45 --------------- Red phosphorus dissolves in concentrated sulphuric acid, when it is strongly heated.
EXPERIMENT 46 --------------- Potassium bromate reacts with aluminium powder with a very bright light and with crackling noise, but the mix is not like flash powder. Some sulphur is needed for easy ignition of the mix. When a tiny amount of red phosphorus is added to the mix, then it is ignited even more easily, but then it also burns exceptionally fast, almost explosively.
EXPERIMENT 47 --------------- Antimony trioxide dissolves in hydrochloric acid, giving a colorless solution. When hydrogen sulfide is passed through such a solution, then a small amount of a yellow precipitate is formed and the liquid becomes very pale yellow. On dilution, much more precipitate is formed and the surprisingly, the color shifts from pale yellow to orange. The orange solid must be hydrous Sb2S3.
EXPERIMENT 48 --------------- Antimony trioxide does not dissolve in concentrated nitric acid, not even when the liquid is heated to boiling. When some hydrochloric acid is added as well, then it quickly dissolves, producing a colorless gas as well. It is oxidized to the +5 oxidation state. When this solution is diluted, then a white precipitate is formed. This white precipitate must be hydrous Sb2O5. When a dilute solution of sodium sulfide is added to this still strongly acidic solution, then H2S bubbles out of solution, but also a lot of precipitate is formed, which has a beautiful bright orange/red color.
EXPERIMENT 49 --------------- A mix of potassium perchlorate and sulphur cannot easily be ignited. When just a tiny pinch of red phosphorus is mixed in, then the mix is ignited very easily and it burns very fast with a bright flash.
EXPERIMENT 50 --------------- A clock reaction that precipitates antimony sulfide.
EXPERIMENT 51 --------------- Sodium sulfite reacts vigorously with 68% nitric acid.
EXPERIMENT 52 --------------- Sodium sulfite is not capable of reducing CrO3, dissolved in acetyl chloride. As soon as water is added, the red color of the hexavalent chromium disappears and green/blue trivalent chromium is formed.
EXPERIMENT 53 --------------- Iodine dissolves in thionyl chloride. It does not react. It gives a purple solution, looking very similar to a purple solution of iodine in an alkane or chlorinated hydrocarbons.
When water is added, then a remarkable reaction occurs. Sulphur is formed.
EXPERIMENT 54 --------------- Sulfur is an extremely fascinating element in that it is capable of existing in a wide range of oxidation states under normal conditions, from -2 (as in Hydrogen sulfide) up through +6 (sulfuric acid). The following experiment demonstrates simple redox chemistry involving Sulfur dioxide gas created in situ.
EXPERIMENT 55 --------------- 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 56 --------------- Arsenate does not form thioarsenates when sulfide ion is added. On acidification, the sulfide is oxidized though by the arsenate.
EXPERIMENT 57 --------------- Arsenic in oxidation state +5 is not easily reduced to elemental arsenic, except by tin(II) chloride.
EXPERIMENT 58 --------------- 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 59 --------------- Triethylamine frequently is used in reactions, where thionyl chloride is used, in order to capture any HCl formed in the reaction. However, when the only reactive compounds are thionyl chloride and triethylamine, then these two compounds react by themselves, giving rise to formation of black material, which sticks to the glass and is difficult to remove.
EXPERIMENT 60 --------------- Dichromate ion oxidizes thiosulfate easily in acidic media, but in neutral media it only is oxidizing incompletely, and a solid compound is formed.
EXPERIMENT 61 --------------- 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 62 --------------- The tetrathionate ion is much more stable than the thiosulfate ion in acidic solution.
EXPERIMENT 63 --------------- Iodine dissolves somewhat in chlorosulfonic acid with a brown color.
EXPERIMENT 64 --------------- 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 65 --------------- A mix of aluminium powder and potassium permanganate is hard to ignite. When a small amount of sulphur is added, then the mix is easily ignited, and a very bright and fast burning flash is produced.
EXPERIMENT 66 --------------- Thionyl chloride and copper nitrate react with each other, giving gaseous products and solid anhydrous copper(II) chloride remains behind.
EXPERIMENT 67 --------------- 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 68 --------------- Peroxodisulfate ion gives a deep brown complex with silver ions in nitric acid. Oxone (peroxomonosulfate) does not give such a complex, actually, it quickly destroys such a complex.
EXPERIMENT 69 --------------- Sulphur dissolves in carbon disulfide exceedingly easily.
EXPERIMENT 70 --------------- Copper(II) ion and sulfite ion react in aqueous solution. A dirty green/yellow precipitate is formed when solutions with these ions are mixed. When there is excess sulfite, then on slight heating the precipitate redissolves and the liquid becomes colorless.
Apparently a coordination complex is formed with copper(I). This coordination complex is very air-sensitive. It reacts with air, giving a dirty brown/green/yellow precipitate.
EXPERIMENT 71 --------------- Carbon disulfide slowly reacts with an aqueous solution of sodium sulfide. The resulting solution finally becomes deep orange.
EXPERIMENT 72 --------------- Chlorosulfonic acid is an extremely reactive compound. It reacts violently with many salts of oxoacids.
EXPERIMENT 73 --------------- Copper(II) ions form no complex with tetrathionate ion and there also is no formation of a precipitate. Even boiling does not cause a visible change.
EXPERIMENT 74 --------------- 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 75 --------------- 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 76 --------------- 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.
End of results for 'S'
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