weiming1998
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Insoluble salts
If HCl is added to Ag2SO4, then H2SO4 and 2AgCl will form, right? AgCl is much less soluble than Ag2SO4 and thus, the precipation will drive the
reaction forward. So I have been looking for a sulfate and a particular acid that if combined, a precipation forms. The first option is iron oxalate,
but it forms stable, soluble complexes in acidic solutions. Does any of you know precipates that will not react with cold, dilute H2SO4(carbonates
won't work!)/won't form soluble complexes?
Of course, I could Google, but I'll have to look through thousands of salts and acids. I wouldn't prefer that.
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phlogiston
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Lead phosphate?
3 seconds of googling yields the following table:
http://www.saltlakemetals.com/SolubilityProducts.htm
lead phosphate sol. prod = 1.6 x 10-32
whereas lead sulphate = 1.6 x 10-8
There must be others.
I suspect the process will be very slow though.
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AirCowPeaCock
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AgCl is soluble in concentrated sulfuric acid. Maybe if you dilute the HCl to say, 10% you could get an appreciable equilibrium. But they you end up
with something like 1.5 molar solution.. hardly worth it if you ask me.
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weiming1998
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CuSO4+Pb does not make much PbSO4 at all, and a hot NaHSO4 solution does not corrode Pb. I could use a battery, but I don't own an old car batery
right now.
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AirCowPeaCock
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you could...oh..western Australia..good luck... Lead sulfate shouldn't be too hard to get, even there. But I don't know if Lead sulphate is the way
to go, they both are pretty insoluble. It's gonna take, oh, I have to imagine weeks for a small amount of dilute sulfuric acid. Ever thought of
oxidation of sulfur dioxide/sulfurous acid? I have to imagine you can get sulfur, can't you?
[Edited on 2-3-2012 by AirCowPeaCock]
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weiming1998
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Quote: Originally posted by AirCowPeaCock  | | AgCl is soluble in concentrated sulfuric acid. Maybe if you dilute the HCl to say, 10% you could get an appreciable equilibrium. But they you end up
with something like 1.5 molar solution.. hardly worth it if you ask me. |
At least more efficient than bubbling SO2 through water, then oxidizing with air/MnSO4 catalyst.
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AirCowPeaCock
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| Quote: Originally posted by weiming1998 | | Quote: Originally posted by AirCowPeaCock | | AgCl is soluble in concentrated sulfuric acid. Maybe if you dilute the HCl to say, 10% you could get an appreciable equilibrium. But they you end up
with something like 1.5 molar solution.. hardly worth it if you ask me. |
At least more efficient than bubbling SO2 through water, then oxidizing with air/MnSO4 catalyst.
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Oxidize in solution, you can get 3% H2O2 right?
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phlogiston
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| Quote: | | CuSO4+Pb does not make much PbSO4 at all, and a hot NaHSO4 solution does not corrode Pb. I could use a battery, but I don't own an old car batery
right now. |
Copper acetate does dissolve lead quite well. Then add any available soluble sulphate (MgSO4 and K2SO4 are common fertilizers) to precipitate lead
sulphate.
Alternatively, electrolyse a sodium carbonate solution with a lead anode, and lead carbonates/hydroxides should start flaking off. I haven't tried
that though with lead (but with many several metals always with good success). Then dissolve in acetic acid and proceed as above.
Or use the old-fashioned way of making lead oxide pigment (look up white lead). IIRC it involves beer, which is always good IMO 
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weiming1998
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Oh come on, 100mls of 3% H2O2 costs 5 dollars here! 34grams of H2O2 will oxidize 64 grams of SO2 to 98 grams of sulfuric acid. So, 11 100ml bottles of
H2O2 (55 dollars!) And 32 grams of sulfur (but I cannot burn sulfur and collect its gases[no oxygen!] without combining an oxidizer, and combining an
oxidizer will make the SO2 evolve so fast it will literally blow up my container!) Or 158 grams of sodium thiosulfate (costs something like 20-30
dollars, plus I'm never, ever going to Sigma Chemicals every again!) So after 80 dollars of investment, I get only 100 grams of sulfuric acid
(assuming no losses of acid from boiling, etc). Better to buy it from eBay, which has it listed as 20 dollars of 950 mls.
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weiming1998
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| Quote: Originally posted by phlogiston | | Quote: | | CuSO4+Pb does not make much PbSO4 at all, and a hot NaHSO4 solution does not corrode Pb. I could use a battery, but I don't own an old car batery
right now. |
Copper acetate does dissolve lead quite well. Then add any available soluble sulphate (MgSO4 and K2SO4 are common fertilizers) to precipitate lead
sulphate.
Alternatively, electrolyse a sodium carbonate solution with a lead anode, and lead carbonates/hydroxides should start flaking off. I haven't tried
that though with lead (but with many several metals always with good success). Then dissolve in acetic acid and proceed as above.
Or use the old-fashioned way of making lead oxide pigment (look up white lead). IIRC it involves beer, which is always good IMO |
I'll try the lead+copper acetate. it might not be useful for precipating, but I might use it to create other lead salts.
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AirCowPeaCock
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EBay sounds great! But just so you know. Sulfur burns just fine in atmospheric oxygen. Nurd rage has a somewhat messy video on how to make sulfuric
acid from sulfur. Sodium metabisulfite works great too! Really 100 ml for 5$! I can get a L for 3 bucks! Western Australia is a sad place for the
amateur chemist!
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weiming1998
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| Quote: Originally posted by AirCowPeaCock | | EBay sounds great! But just so you know. Sulfur burns just fine in atmospheric oxygen. Nurd rage has a somewhat messy video on how to make sulfuric
acid from sulfur. Sodium metabisulfite works great too! Really 100 ml for 5$! I can get a L for 3 bucks! Western Australia is a sad place for the
amateur chemist! |
No, the hydrogen peroxide is sold in 100ml bottles in every pharmacy I went to. Some don't even sell H2O2 at all! Sodium metabisulfite releases 2
moles of SO2/mole, so that might be better, but I am not sure about the legal status of home-brewing here. Also, sulfur wouldn't burn because the
container is entirely closed (prevent SO2 from escaping!). And SO2 is heavier than air. So the resultant SO2 covers the sulfur, smothering it. Any
idea on how to keep the SO2 from smothering the sulfur?
I found this video, and the person used a fish pump. http://www.youtube.com/watch?v=xHLeFSY_OJU
Could I put an ozone generator (produces mainly air) into the can, and another tube to lead the SO2 out? Or would the sulfur dioxide be so heavy that
the bubbles produced on the other end are the air that I just pumped through?
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watson.fawkes
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If you cannot buy hydrogen peroxide, I'm guessing the next-best route to H2SO4 is the lead chamber process. Search for the thread
titled "H2SO4 by the Lead Chamber Process - success" here. The Wikipedia article is also informative.
Note: Since I'm guessing that you can't get nitrates either, you'll have to use gaseous nitrogen oxides (NOx) instead. This means working with high
voltage and setting up an arc generator to burn air. This is also a way of getting to nitric acid, but in the lead chamber process you don't need to
dissolve the NOx in water first, meaning you don't need an absorption tower, just the arc generator.
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weiming1998
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| Quote: Originally posted by watson.fawkes | If you cannot buy hydrogen peroxide, I'm guessing the next-best route to H2SO4 is the lead chamber process. Search for the thread
titled "H2SO4 by the Lead Chamber Process - success" here. The Wikipedia article is also informative.
Note: Since I'm guessing that you can't get nitrates either, you'll have to use gaseous nitrogen oxides (NOx) instead. This means working with high
voltage and setting up an arc generator to burn air. This is also a way of getting to nitric acid, but in the lead chamber process you don't need to
dissolve the NOx in water first, meaning you don't need an absorption tower, just the arc generator. |
I looked at the price for a high-voltage transformer. 200 dollars????? Also, I don't think that the high-voltage thing is safe enough for me (I
haven't worked with voltages higher than a 9 volt battery)
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AirCowPeaCock
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This is not the same video, but it might give you some ideas. http://www.youtube.com/watch?v=xHLeFSY_OJU
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weiming1998
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Nevermind, I've got some potassium nitrate now, so I can try the lead chamber process. Surprisingly, the potassium nitrate was found in a Chinese food
shop, in the spice section. I have never though of looking there.
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