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February 9 2012 5 09 /02 /February /2012 19:18

This is the public version of the diary of my personal chemistry experiments. The removal of personal and other sensitive information is marked with “[redacted]”. Use Control + F to find what you want in here.

Past

Tin oxidation: tin is heated on an element (heating element), creating some smoke and white tin(IV) oxide.

Lead oxidation: lead is heated on an element, creating some smoke and yellow lead(II) oxide

Magnesium ignition: Magnesium rod ignited in a candle, though with difficulty. Further attempts to ignite magnesium ribbon using candle were unsuccessful. Magnesium ribbon ignited easily when heated on an element. The residue is white magnesium oxide, and the flame is almost pure white and bright enough to hurt eyes.

Lead iodide formation: tincture of iodine was reduced by ascorbic acid to make an iodide solution. Lead was dissolved in acetic acid/hydrogen peroxide, leaving a residue of (likely) antimony and tin. These solutions were mixed to precipitate a bright yellow precipitate of lead iodide.

Iodide formation: Tincture of iodine was reduced by ascorbic acid to make an iodide solution. The iodide is colorless and partially consists of sodium iodide.

Lead chloride formation: Lead chloride was not formed by reacting sodium chloride with the previously prepared lead acetate solution because the Pb(Ac)2 was too dilute. Reaction with hydrochloric acid precipitated the white chloride, however.

Lead bromide formation: An attempt to synthesize lead bromide by the reaction of the previously mentioned Pb(Ac)2 solution with sodium bromide was unsuccessful.

Magnesium dissolution in acetic acid: magnesium dissolves relatively slowly in 5% acetic acid, liberating hydrogen. Zinc, by comparison, underwent no reaction in about 10 minutes, although it has been previously shown to undergo a reaction upon standing.

Copper(II) chloride aluminium reaction: Copper(II) chloride was reacted with aluminium foil shreds to form hydrogen, aluminium hydroxide, copper, and aluminium(III) chloride in a violent reaction.

Galinstan coating removal: When galinstan is properly applied to aluminium foil, it dissolves the protective layer, making it susceptible to aerial and aqueous oxidation. Flaking of aluminium oxide was observed coming from the point of application of the galinstan. The galinstan-coating aluminium also reacted with water, creating hydrogen gas, aluminium hydroxide, and re-precipitating the galinstan as liquid metal beads.

Lithium air reaction: Lithium was put in a closed bag where a limited amount of air was available. It first blackened and then decomposed into a white oxide/carbonate layer. Apparently, either the bag had too much air or the seal was not working as very little nitride was produced. Only the faintest smell of ammonia was present after combination of the oxide/carbonate with water.

Carbon monoxide detector dismantlement: The fuel cell in a CO electrochemical sensor was disassembled. A canister containing an unknown electrolyte (not sulfuric acid) was present, as well as several Teflon sheets found to be impregnated with platinum. The material of the canister is yet to be determined, as it is slightly magnetic. (Later determined to be nickel-plated aluminium.)

12-3

Lead sulfate formation: The previously mentioned Pb(Ac)2 solution reacted with magnesium sulfate to form a white precipitate of lead sulfate.

Ammonium chloride smoke: Tissues were soaked with ammonia and hydrochloric acid and brought near each other. The vapors combined to create a white smoke of ammonium chloride, which was slightly noxious.

Carbon monoxide detector electrochemical cell electrolyte test: According to Wikipedia, most contain sulfuric acid. Mine did not appear to contain it, as a pH test showed a neutral pH. Hardly any residue was left behind after evaporation.

12-8

NdFeB magnet dissolution: A neodymium magnet is dissolved in HCl. The reaction is moderately rapid, with the solution turning yellow-green.

12-9

NdFeB magnet dissolution: The solution has turned a red-green color, from the combined colors of neodymium and iron (possibly praseodymium) chloride. Upon evaporation with hair dryer, it fumed strongly but eventually crystallized as greenish crystals, which continue to release excess HCl. The boron powder was insoluble in HCl and precipitated, but was accidentally lost. The crystals show a tint of red when photographed in non-fluorescent light as a result of the neodymium.


Triiodide electrolysis: An attempt to produce iodine by electrolytically oxidizing triiodide was conducted. The attempt was successful at 5V; the reduced occurrence of oxygen gas helped prevent the carbon anode from erosion. Additional triiodide was added as the iodine yield was less than desired, although the solution was practically colorless. The iodine was filtered. Because of the lack of heating with 5V electrolysis, the alcohol (which did not evaporate extensively) began dissolving the iodine as soon as the electrolysis stopped. The experiment was repeated using 24V, with which the iodine is produced rapidly (10 minutes) and there is much heating of the solution. Iodine can be differentiated from carbon impurities by its sheen; carbon has no reflection capabilities.

NdFeB magnet dissolution: An Nd magnet is again dissolved in HCl, with an attempt being made to separate boron upon reaction completion. The (II) oxidation state of iron may be taken advantage of in order to separate most of the iron from the neodymium chloride. I got HCl acid in my hair from the earlier drying experience.

12-10

Iodine production: iodine can also be separated from carbon by its evaporation rate; my iodine disappeared overnight, despite near-freezing temperatures, leaving dirty filter paper behind.

NdFeB magnet dissolution: Is it NdFeB? There is not B precipitate. However, a magnetic precipitate shown to be nickel or cobalt (nickel is much more likely) by its very slow dissolution in HCl was formed, probably from the corrosion-resistant coating. On later examination, boron in an almost colloidal form had fallen to the bottom of the container. This ultrafine powder mostly passes right through a tissue and so cannot be collected and dried in small quantities. Upon dissolution of a large magnet, a measurable amount of boron dust may be collected.

NdFeB magnet work: The acidic chloride solution was neutralized with sodium carbonate to create a white precipitate that turned brown, similar to manganese. Upon addition of hydrogen peroxide, violent fizzing occurred and a dark red flocculent precipitate appeared to form. The pH was around 7. Some HCl was added to raise the pH to around 2. The dark red precipitate dissolved to form a deep dark red solution whose identity is unknown. Upon addition of more HCl, it lightened to a yellow solution, looking just like an iron(III) chloride complex. When a base is added, a bright red-brown precipitate is formed. The pH was changed to about 4 and the solution filtered. Other than a little iron that leaked through the filter paper, no soluble rare earth metal ion passed through the paper as evidenced by a lack of precipitation when ammonia is added to the filtrate.

Cobalt production: A dilute aqueous solution of cobalt(II) chloride in hydrochloric acid was electrolyzed with a carbon anode and a brass cathode. Practically no cobalt was produced (as evidenced by a magnet sweep), probably because of the dilution.

12-12

Iodine production: Triiodide is reduced with ascorbic acid. Due to an unfortunate accident, an iron solution contaminated the iodide, but it should still be usable. The plan is to evaporate the alcohol, then oxidize the iodide directly to iodine.

NdFeB magnet work: Other than some of the precipitate falling into the iodide solution, nothing happened. A slight color change is noticed when the precipitate is photographed in fluorescent vs. xenon light, but it seems as if I do not have the resources to extract the neodymium. In that attitude, the precipitate was disposed of.

Lead dissolution: I poured off most of the lead solution and added hydrochloric acid to the residue. Lead(II) chloride precipitated, which dissolved in additional acid. The gray precipitate dissolved without much hesitation in a way that made it seem like tin. A test with copper(II) chloride can be used to determine if tin(II) is present. Triiodide seems to have been reduced by the solution.

12-13

Cobalt production: Reduction of acidic cobalt(II) chloride solution by magnesium metal produced, along with vigorous bubbling, pure cobalt metal, as evidenced by its magnetism.

Lithium chloride production: Lithium hydroxide prepared by reacting lithium with water had absorbed carbon dioxide through the container lid gaps and turned into lithium carbonate. This was placed in hydrochloric acid. It dissolved to form a colorless solution of lithium chloride. This can be used to make a flame test.

Magnesium iodide work: Magnesium metal was placed in dilute triiodide solution to determine if reduction would take place. No reduction happened, even after acidification with acetic acid. Reduction of the acid and/or water was only observed, with hydrogen being produced.

Magnesium reduction of magnet chloride: Iron was produced, as evidenced by the magnetism of the magnesium piece. However, the iron dissolved as fast as it was formed in the acidic solution. After the acidity declined, more iron was precipitated, however. Eventually, the iron started oxidizing to iron(III) hydroxide.

Mischmetal separation: After grinding of mischmetal, a black powder remained. It appears to be a magnetic oxide. The rare earth oxides cannot be separated from the iron oxide, unless it is the metal after all. The metal is slightly magnetic itself, so that is a possibility.

Mischmetal reactions: Mischmetal reacts very slowly with hot water, similar to magnesium. When some acetic acid is added, dissolution begins occurring, despite the extreme dilution of the acetic acid (1%). The rare earths are preferentially oxidized, as evidenced by a magnet. Upon addition of bleach, a yellowish-white precipitate is formed, looking a lot like cerium(IV) oxide. Upon addition of acetic acid, it re-dissolves to form a yellow solution.

12-14

Iodine extraction: The almost evaporated solution of iodide mixed with ascorbic acid was electrolyzed. Because the iodine was being reduced as fast as it was being oxidized, bleach was added to speed up the reaction. An instant precipitate of iodine formed, along with much heat. The iodine was then re-dissolved, and the solution became green. The green appears to be an oxidation product of ascorbic acid by bleach. Little bleach was present according to a hydrochloric acid test. When the solution was reduced with additional ascorbic acid, it formed blue-gray iodine crystals as an intermediate; the miniscule quantity is shown on the filter paper below. Most of them immediately dissolved to make brown triiodide, which was reduced to colorless iodide. The oxidation state of iodine in the clear solution upon oxidation of bleach is yet to be reported. The colorless iodide is electrolyzed.

12-15

Iodine production: Iodine blew away. Found a week later in the hedge.

Mischmetal reactions: Another piece of mischmetal is dissolved in acetic acid. A slow reaction was observed in a highly dilute bleach(?) solution. The magnetic precipitate that formed was dissolved in additional acetic acid. The solution is not coloring and the precipitate remains magnetic despite thinning, evidence that the iron is not dissolving in the diluted acetic acid solution. Instead, the precipitate appears to be a magnetic iron-lanthanide mixture with more iron than before.

Magnesium and zinc dissolution: Magnesium and zinc were placed in hydrochloric acid and videotaped doing their thing.

12-16

Mischmetal reactions: The iron-lanthanide hypothesis expressed before is true. The mischmetal acetate solution darkened considerably overnight, while the one with the more recent dissolution remains practically colorless. Below are pictures of before and after standing.

Magnet dissolution: An NdFeB magnet is placed in acetic acid, with hopes that the iron will not dissolve and the resulting solution will not be so caustic. It dissolves very slowly, producing hydrogen and an almost colorless solution.

Battery dissection: The NiCd battery came apart without much trouble. The cadmium appears to be in a fine compacted powder form, not an electrode form. The nickel electrode shows some evidence of green nickel(II) hydroxide at certain locations. The electrolyte papers (seen with the Ni roll) are placed in water to dissolve the KOH and then neutralized with HCl to form KCl. The original solution had a pH of >10. The final solution is soaked into the porch through a hole on the bottom of the container and ate away the paint KFortunately the spot is small enough. A successful math lab project is visible in the background of this photo.

 

 

 

 

Mischmetal reactions: I evaporated the solution of mischmetal acetate to a small puddle by a blow dryer, which crystallized upon cooling. The crystals appear syrupy, as there is probably acetic acid left in them. After placing in the freezer, they remain syrupy. Upon dissolving in water, they are completely soluble, showing that no insoluble oxy-acetate has formed. It appears that the solution has gotten a little darker again, although not much darker.

Cadmium production: The “cadmium” anode from the nickel-cadmium battery was placed in diluted HCl. Chlorine(!) was evolved, and black slime filled the solution. No hydrogen seems to be produced.

Cd

Ni

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