Fantasma4500
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steel chloride solution reacts with ammonia?
as i was testing a metal for aluminium i decided to try with iron aswell to see if it reacted as ive seen it does, my pipette had some 25% NH4OH in it
still, and i had a solution containing iron from electrolysing HCl with steel as anode, to test if it really was steel (precipitation chromium
hydroxide/carbonate with Na2CO3)
it shows up it really was steel tho it was coated with zinc
anyways, what happened was that when i put the pipette in the beaker with iron (and probably nickel aswell) it turned into a weird bluish dark slurry
where the pipette (ammonia) got in contact with it..
shortened down: has the ammonia reacted with the iron or the nickel or even the chrome in solution?
the solution was run through a filter to remove the chrome insolubles for dichromate, so theres also Na2CO3 in the solution, and possibly nickel /
iron carbonate
it would be quite useful to extract nickel from steel (:
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AJKOER
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I suspect that you have formed a double salt with Iron & Ammonia (Ferrous Ammonium Chloride is a candidate, for example). Other combinations with
ammonia I quess are also possible. The good news is that these salts are distinctly colored. So use this in identifying your salt.
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blogfast25
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Quote: Originally posted by AJKOER  | | I suspect that you have formed a double salt with Iron & Ammonia (Ferrous Ammonium Chloride is a candidate, for example). Other combinations with
ammonia I quess are also possible. The good news is that these salts are distinctly colored. So use this in identifying your salt.
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And I suspect you’re wrong.
Firstly, he mentions a slurry: that implies precipitation. Most ferrous double salts are highly soluble.
Secondly, most ferrous double salts are light coloured. If you have examples of deeply coloured ones, please provide references.
Unfortunately Antiswat provided precious little information re. the actual conditions but assuming the iron was ferrous, fairly concentrated and there
was enough ammonia to neutralise the excess acid, then a precipitate of Fe(OH)2.nH2O is the most likely cause of the slurry. Also, if through air
oxidation there was also some Fe (III) present, then dark coloured magnetite (Fe3O4) could have formed.
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Fantasma4500
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| Quote: Originally posted by blogfast25 | | Quote: Originally posted by AJKOER | | I suspect that you have formed a double salt with Iron & Ammonia (Ferrous Ammonium Chloride is a candidate, for example). Other combinations with
ammonia I quess are also possible. The good news is that these salts are distinctly colored. So use this in identifying your salt.
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And I suspect you’re wrong.
Firstly, he mentions a slurry: that implies precipitation. Most ferrous double salts are highly soluble.
Secondly, most ferrous double salts are light coloured. If you have examples of deeply coloured ones, please provide references.
Unfortunately Antiswat provided precious little information re. the actual conditions but assuming the iron was ferrous, fairly concentrated and there
was enough ammonia to neutralise the excess acid, then a precipitate of Fe(OH)2.nH2O is the most likely cause of the slurry. Also, if through air
oxidation there was also some Fe (III) present, then dark coloured magnetite (Fe3O4) could have formed.
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hm, well i have played around with Fe3O4, and this isnt Fe3O4 for sure.. (: its very deeply blue coloured, it seperates from the water and it have a
Fe2O3 layer on top (iron carbonate it could be perhaps also?)
but the iron or metal i used, it showed that it was steel, thereby assuming it is Fe Cr and Ni as im not sure how many steel types that doesnt contain
nickel..
FeCl3 + CrCl3 + NiCl2 + Na2CO3 > NiCO3 + FeCO3 + Cr(OH)2
theres something strange at this, because i dont get much other precipitate than the chromium at this point which is as some strange slurry (ive done
this some times in order to make Cr2O7 later on)
NiCO3 and FeCO3 should be insoluble unless i missed something.. (:
but that would leave back the nickel and the iron to react with the ammonia, i honestly dont know anything about ammonia complexes with iron and
nickel, but as i added the ammonia it reacted with some of the metal ions to form a precipitate..?! shouldnt it already have reacted with the Na2CO3?
i think ill go ahead and heat it up, then i can decompose the complex slowly and see if i get a rust like leftover, if that then im probably left with
something around iron.. if it doesnt act like iron oxides then i probably isolated nickel, tho i doubt it because there was quite alot of precipitate,
kinda mushy fluffy and light..
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blogfast25
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The best way out of this is to repeat the experiment, this time in better controlled conditions. Take account of the quantities and concentrations of
reagents used and final pH value.
FeCl3 cannot yield FeCO3 and Fe (III) carbonate does not exist.
CrCl3 yields Cr(OH)3, not Cr(OH)2.
From acid solutions of stainless steel (12 % Cr), alkalis co-precipitate Fe and Cr.
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zed
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I would avoid letting this complex salt, dry out. At least, until I was sure of its stability.
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Fantasma4500
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| Quote: Originally posted by blogfast25 | The best way out of this is to repeat the experiment, this time in better controlled conditions. Take account of the quantities and concentrations of
reagents used and final pH value.
FeCl3 cannot yield FeCO3 and Fe (III) carbonate does not exist.
CrCl3 yields Cr(OH)3, not Cr(OH)2.
From acid solutions of stainless steel (12 % Cr), alkalis co-precipitate Fe and Cr. |
about the iron carbonate: im very sure it is possible to produce as i have done it myself from iron chloride, to then decomposing the iron carbonate
(just threw a small ~1g chunk out the other day when cleaning up)
i used this as a route to Fe2O3, but found out that Fe3O4 > Fe2O3 was better in many ways
but im unsure about those ions you dont really hear much about, honestly have no clue how to find out or calculate if it should be Cr(OH)2 or Cr(OH)3,
i mean it could be both..
but i think i have an idea of how i could possibly find out abit more about this.. yet another ''x'' compound
ill decompose it, as far as i have seen tetraammines decompose relatively easily, so it should leave me with Fe2O3 AT SOME POINT if it really is iron
based.. if not then something with iron in still, that i would be able to turn into Fe2O3
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Fantasma4500
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| Quote: Originally posted by zed | | I would avoid letting this complex salt, dry out. At least, until I was sure of its stability. |
you sparked and idea ive walked blind by many times (:
its not in filter and its getting somewhat dry but it cannot completely dry out at this time anyways, i think ill partially take your advice and store
it abit moist in filter, in a plastic bag and take small amounts of this ''compound x'' and heat it up
slowly and violently
hopefully i will get some loud results, but doubt theres a high chance of it..
would make the left over solution from dichromate further useful no matter what i decide this compound is, sounds like i have possibly isolated one of
the metal ions in the solution
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DraconicAcid
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| Quote: Originally posted by Antiswat |
but im unsure about those ions you dont really hear much about, honestly have no clue how to find out or calculate if it should be Cr(OH)2 or Cr(OH)3,
i mean it could be both.. |
In most simple precipitation reactions, the ions do not change charge. If you start with CrCl3, that contains Cr3+ ions. These
will precipitate with hydroxide to give Cr(OH)3.
Cr(II) compounds tend to be very air-sensitive in aqueous solution, and will react with oxygen to give Cr(III) compounds. Iron(II) compounds are
stable in acidic solution, but will react readily with oxygen in basic solutions (due to the much greater insolubility of Fe(OH)3 than
Fe(OH)2).
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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blogfast25
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| Quote: Originally posted by Antiswat |
about the iron carbonate: im very sure it is possible to produce as i have done it myself from iron chloride, to then decomposing the iron carbonate
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FeCO3, yes. Fe2(CO3)3, no. The latter doesn't exist in watery medium. Carbonate solutions cause Fe(OH)3 to precipitate from ferric solutions, NOT
Fe2(CO3)2. Same as Al and Cr(III).
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