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CHRIS25
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Aluminium ChloroSulphate Crystal
Al2(SO4)3.14/15H2O + HCl = AlClSO4.6H2O But the object was to create a crystal.
Method:
2g Al Sulphate in 5 mLs 37.5% 1.19 SG HCl
Boiled vigorously for 3 minutes
Heated gently for a further 30 minutes left 2.5 mLs of soln in boiling tube.
Air Cooled
Result:
Failure
Two images show the solution and then the solid I extracted after cooling.
 
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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aga
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Ah Jesus.
Here we go again !
The photo looks very much like a crystal.
What's wrong with it ?
[Edited on 2-6-2014 by aga]
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woelen
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What purity of chemicals did you use? The solid material is yellow and this can never be a pure sample of AlClSO4.6H2O. The latter compound almost
certainly must be colorless (or white).
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aga
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Quote: Originally posted by woelen  | | this can never be a pure sample of AlClSO4.6H2O. The latter compound almost certainly must be colorless (or white). |
Could you please describe the expected product in terms of possible colours, and textures ?
It would be a great help.
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DraconicAcid
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| Quote: Originally posted by aga | | Quote: Originally posted by woelen | | this can never be a pure sample of AlClSO4.6H2O. The latter compound almost certainly must be colorless (or white). |
Could you please describe the expected product in terms of possible colours, and textures ?
It would be a great help. |
Halide ions are colourless. Sulphate ions are colourless. Aluminum ions are colourless. Any combination of the above will be either white or
colourless, depending on the size of the crystal.
Colours result from the the absorption of visible light. This will only happen in systems that have a) conjugated pi bonds, b) partially-filled d
orbitals, or c) the possibility of internal redox reactions (charge transfer). Aluminum doesn't have any of these, and won't form a coloured compound
unless its counterion has them.
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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aga
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Wow !
Thanks very much for the comprehensive explanation of the ion colours, and also of the Why.
This goes in the Book for sure.
As i will try this experiment tomorrow, could you please give a clue as to the expected texture of the dried crystals, if they do in fact dry at all.
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CHRIS25
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| Quote: Originally posted by woelen | | What purity of chemicals did you use? The solid material is yellow and this can never be a pure sample of AlClSO4.6H2O. The latter compound almost
certainly must be colorless (or white). |
HCl is Lab quality 37
Aluminium Sulphate I made myself from Lab Quality Sulphuric acid and Aluminium Piping, but the latter was filtered and a clear solution was achieved.
The whole solution started to turn yellow within seconds of heating - what about the colour of a chloride ion, tetra chlorocopper is yellow, and
chlorine gas is yellowish/green?
Ishould perhaps also add that I had the boiling tube suspended between a stainless steel wire rack over the heat, because of wind outside I had it
slightly covered as well. after 15minutes or so the stainless steel was covered in yellow, it washed off very easily but has stripped the steel of
its bright lustre, no problem about this rack, but I thought I would mention it because of the colour of the residue deposited.
[Edited on 2-6-2014 by CHRIS25]
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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DraconicAcid
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| Quote: Originally posted by CHRIS25 | | The whole solution started to turn yellow within seconds of heating - what about the colour of a chloride ion, tetra chlorocopper is yellow, and
chlorine gas is yellowish/green? |
Chloride ion is colourless (see sodium chloride for an example). Chlorine gas is a different substance, and transition metal complexes with chloride
ions have partially-filled d orbitals to explain their colour. I would suspect that the yellow colour is a copper or iron impurity.
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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The Volatile Chemist
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| Quote: Originally posted by CHRIS25 | | Quote: Originally posted by woelen | | What purity of chemicals did you use? The solid material is yellow and this can never be a pure sample of AlClSO4.6H2O. The latter compound almost
certainly must be colorless (or white). |
HCl is Lab quality 37
Aluminium Sulphate I made myself from Lab Quality Sulphuric acid and Aluminium Piping, but the latter was filtered and a clear solution was achieved.
The whole solution started to turn yellow within seconds of heating - what about the colour of a chloride ion, tetra chlorocopper is yellow, and
chlorine gas is yellowish/green?
I should perhaps also add that I had the boiling tube suspended between a stainless steel wire rack over the heat, because of wind outside I had it
slightly covered as well. after 15minutes or so the stainless steel was covered in yellow, it washed off very easily but has stripped the steel of
its bright lustre, no problem about this rack, but I thought I would mention it because of the colour of the residue deposited.
[Edited on 2-6-2014 by CHRIS25] |
I don't know about chlorine gas, but the chlorine-copper complexes get their color from copper. The steel may somehow have influenced the coloration,
eg. stirring sodium tetrachlorocuprate(II) with a steel screwdriver seemed to etch the upper layer.
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blogfast25
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Chris:
This could be as much a success as a failure, right now we don't know that. It's rather encouraging that a solid material did form!
The yellow colour is almost 100 % certain Fe<sup>3+</sup>. Possibly from the HCl, in which ferric chloride is a common contaminant. You
said it was 'lab quality': where did you get it? Test for Fe3+ with thiocyanate.
What's the consistency of this material? Hard/soft/mushy?
Does it dissolve in water and is the solution clear?
The real challenge is now to figure out the composition of the material, i.o.w. does its composition correspond to AlClSO4.6H2O?
If this compound did form then stoichiometrically what happened was:
Al<sub>2</sub>(SO<sub>4</sub> <sub>3</sub> + 2
HCl + 6 H<sub>2</sub>O === > 2 AlClSO<sub>4</sub>.6H<sub>2</sub>O +
H<sub>2</sub>SO<sub>4</sub>
[Edited on 2-6-2014 by blogfast25]
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CHRIS25
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The only source of iron contamination can be the HCl. My batch contains 0.5 ppm. Whereas a batch from the same company for trace analysis has 0.05
ppm. And yet another batch has 0.1 ppm as we go up in expense.
Blogfast: It dissolves very easily when broken up leaving the water solution clear
I do not have thiocyanate unfortunately.
Consistency is between Hard and soft, but not mushy. Tomorrow I will repeat the experiment but with more heating and try to leave less solution in
tube. But will use 2g of sulphate again.
[Edited on 2-6-2014 by CHRIS25]
[Edited on 2-6-2014 by CHRIS25]
[Edited on 2-6-2014 by CHRIS25]
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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Zyklon-A
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So none of your solution ever touched the SS? If so it must be an impurity in your reagents.
Chlorine gas is very different, it has covalent bonds, chloride anions are always colorless.
How about the purity of your aluminum sulfate? Was the Al pipe tested? Or you sulfuric acid, Is it also lab grade, or drain cleaner/battery acid.
My guess is iron chloride impurities, very small quantities can discolor a solution.
I don't know how the aluminum sulfate could be colorless, but turn yellow in pure hydrochloric acid, doesn't make sense.
You sure the HCl (aq) is pure?
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blogfast25
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Are you sure that there wasn't any iron 'pick up', for instance from a steel spatula or such like?
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CHRIS25
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Ok absolute clear: Not a single bit of the apparatus had any contact at all with anything steel iron, nothing, except glass and I use plastic to
transfer solid chemicals, never metal things. The HCl analysis is 0.5ppm iron, the sulphuric acid is 1ppm iron. Both acids are from a reputable lab
supplier. Yes my Al sulphate sample was and is pure white. The yellow began almost immediately upon heating.
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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The Volatile Chemist
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If you have Tannic acid, you can test for iron complexes with that, or with Potassium Ferro/Ferri-cyanide. The FerroCN makes a blue compound, and the
Tannic acid makes a black prec./complex.
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Zyklon-A
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Well then... I'm stumped.
BTW, the yellow coating on your SS wire thing is likly just from acid aerosols or condensed acid on said wire.
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blogfast25
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I will try and repeat this experiment 'ASAP' [cough!]. It's interesting.
Such an aluminium chlorosuphate could crystallise out from a witches brew of aluminium sulphate and HCl, provided it is less soluble than aluminium
sulphate and less soluble than aluminium chloride. It's entirely possible but requires rigorous proof.
[Edited on 2-6-2014 by blogfast25]
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CHRIS25
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Zyclonb: Yellow coating on stainless steel was condensed acid I know. But would you say that the analysis of both my acids given above provide
sufficient reason for the Iron colour?
Blogfast tomorrow I will do the following: Heat up the concentrated 37.5% acid for a minute to see if that remains clear. Then I will add the
sulphate, probably more this time, I have to say that upon my first attempt not recorded here, I dissolved the sulphate in cold acid and it remained
clear, again, not until heating did the yellow appear. I will see how far I can push the evaporation of Hydrogen chloride before allowing to cool. I
think I could get a more hardened solid.
I have tannic acid and ferricyanide, I will get to work.
[Edited on 2-6-2014 by CHRIS25]
I made a quick tannic acid solution, the colour of very weak tea of course. Placed in a sizeable amount of the yellow solid, absolutely no change in
colour at all, and no precipitate.
[Edited on 2-6-2014 by CHRIS25]
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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Zyklon-A
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| Quote: |
Zyklonb: Yellow coating on stainless steel was condensed acid I know. But would you say that the analysis of both my acids given above provide
sufficient reason for the Iron colour?
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Nope. I doubt the impurities could have come from your acid.
Along with testing your acid by heating, test the sulfate by heating, perhaps that's where the impurity come from.
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CHRIS25
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The sulphate was created yesterday, and it was at near boiling point before being cooled. As I remember, it turned from clear at dilution stage to a
viscous slight off-yellow when concentrated down prior to cooling and getting the alumnium sulphate hydrate. But this was characteristic of the
colour you get from sulphuric acid upon heating, and there was excess sulphuric acid in the aluminium sulphate, so maybe something here? But Blogfast
did the same thing, I wonder whether the colour of his solution prior to cooling was a slight off yellow, or was it totally clear when slightly
viscous?
[Edited on 2-6-2014 by CHRIS25]
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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The Volatile Chemist
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CHRIS!!!! I'll P2P you too, but I forgot, DO NOT add Ferricyanide to your HCl, just in case you didn't know. A neutralized AlClSO4 solution will be
easy to test with ferricyanide, but Hydrogen Cyanide gas evolves if you mix ferricyanide and a strong acid. BE CAREFUL. If the product itself is
acidic in solution, even that could make HCN vapors on mixture w/ HCl. The tannic acid will be fine, though.
Sorry for not saying so earlier, and I apologize if you already knew.
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Brain&Force
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I'm pretty sure the impurity is iron(III) ions. As recommended earlier, I would use thiocyanate to confirm - add some to an HCl sample as well to
determine the source of the impurity.
What is the source of the aluminum sulfate? I would also dissolve some aluminum sulfate (if you have any left over) in hydrogen peroxide and allow
that to dissolve, then add thiocyanate. If it's the metal ion, it may be hiding as iron(II) which doesn't show up for the thiocyanate test.
At the end of the day, simulating atoms doesn't beat working with the real things...
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aga
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Here is a repeat CHRIS25's experiment.
Some Aluminium Sulphate (hydrate unknown) was put in a beaker.
Heated until anhydrous, giving 14.41g
Then the equation was to be balanced, in order to determine how much HCl was required.
This failed to work algebraically.
Not knowing the mechanism or quantities, 23g of 25w% HCl and a splash of DIW were added, mixed and heated.
3 mins rapid Boiling, 30mins gentle heat.
Very quickly the liquid became a pale yellow.
By 20 minutes into the gentle heating, the liquid is clearer, and yellower.
Waiting for the 30 mins to elapse, i attempted to work out what was wrong with the equation.
Al2(SO4)3 + HCl -> ALClSO4 cannot be balanced.
So something else must be going on.
Using CHRIS25's clue regarding ' ...characteristic Sulphuric acid ...', this makes more sense :-
Al2(SO4)3 + 2HCl -> 2ALClSO4 + H2SO4
The sulphuric being in equilibrium with the water.
After 30 minutes the liquid was cooled in a water bath.
A this stage the liquid is yellow, and giving off strong fumes of clorine, which are visible.
After 3 mins cooling, the liquid was transfered to a smaller plastic container and further cooled in a water bath.
At 10 minutes the solution has solidified into a hard yellow mass weghing 18.86g
In colour it is more like elemental sulphur than anything else.
So, it is either contaminated by something with yellow ions, or some other reaction is happening, or the quest for The EarWax Recipie is over.
By the weights, that would make it a .16 hydrate. Does that even exist ?
Source of reactants :-
HCl was from a reputable chem supplier.
Al was from aluminium foil.
H2SO4 was from OTC drain Openener, colour removed with H2O2, boiled
Water is OTC distilled & de-ionised
All implements are glass/plastic in each process.
By the time i finished typing this, the yellow mass has developed white patches, and there is a strong sulphur smell coming from it.
[Edited on 3-6-2014 by aga]
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CHRIS25
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Second Sample
Ingredients:
4 mLs 37.5% HCl
4 g Aluminium Sulphate (14 hydrate)
Method:
HCl was boiled first, took 10 seconds, but boiled for 1 minute
Sulphate was added to the hot HCl
Boiled continuously for 5 minutes
Cooled in Ice bath for 5 minutes
Observations:
The precipitate is Less yellow and harder than yesterday
Reasonings:
I doubt that there is iron contamination by the distinct lessening of yellow in the sample (Twice as much sulphate). Also by doubling the sulphate
and lessening the HCl and boiling continuously I wanted to drive off much more water.
Next step:
Can't think of one just yet.
More Observations:
Point 1. Although not very clear here there are, unlike first sample, far more white areas visible, especially on the underside where the bowl of the
boiling tube was.
Point 2. Yesterdays sample has, for all intense and purposes, melted in its own crystalization, Mmm, the colour has gone from this bright yellow to
the same colour as the sample I have just made, Loss of yellow in other words.
[Edited on 3-6-2014 by CHRIS25]
[Edited on 3-6-2014 by CHRIS25]
‘Calcination… is such a Separation of Bodies by Fire, as makes ‘em easily reducible into Powder; and for that reason ‘tis call’d by some
Chymical Pulverization.’ (John Friend, Chymical Lectures London, 1712)
Right is right, even if everyone is against it, and wrong is wrong, even if everyone is for it. (William Penn 1644-1718)
The very nature of Random, Chance development precludes the existence of Order - strange that our organic and inorganic world is so well defined by
precision and law. (me)
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blogfast25
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@Volatile chemist:
Calm down. Only in highly acidic conditions with heating do ferro/ferricyanides release any HCN. These complexes are very stable. To do the test
safely, just dilute the sample a bit. But ferricyanide won't detect ferric ions, only ferrocyanide does that.
Similarly ferricyanide detects ferrous ions. In both cases Prussian Blue is formed.
@Aga:
The stoichiometry is:
Al2(SO4)3 + 2 HCl + 12 H2O === > 2 AlClSO4.6H2O + H2SO4
Without enough HCl in the solution this product will not form.
I doubt very much you observed chlorine: there's nothing in that mixture that can oxidise chloride to chlorine. I think you saw and smelled HCl.
Chlorine cannot arise spontaneously: something has to oxidise the chlorine ions. That oxidation requires powerful oxidisers, BTW...
@Chris:
To avoid the samples redissolving try this. Immediately after preparation put them in the fridge. When cooled sufficiently try washing with small
amounts of ice cold water, then pat dry with kitchen towel. It's mainly excess solution that clings to the crystals that causes the latter to re-enter
solution, I believe...
To further characterise the material you need to obtain it in a reasonably dry state. Like dried in a CaCl2 desiccator.
So far, the materials obtained look quite different from aluminium sulphate hydrate. That counts for something. My guess remains this is indeed
aluminium chlorosulphate but now we need to prove that!
[Edited on 3-6-2014 by blogfast25]
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