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I use this method to make me CuO. Actually anhydrous cuso4 will start to decompose at about 300C. The 650 figure is the temperature at which it decomps vigorously. The so3 fumes are indeed very choking and irritating. I make it in my room without a fumehood, i just open the window :). wouldn't it be possible to condense the so3 (boiling point 45C) and then add water?


I use this method also to make CuO for one of the chemicals used for

combustion analysis of organic compounds. What might interest others is how I dispose of the SO3. Using a fume hood is difficult when the fumes also violate the local clean air standards. A (costly) permit would be required. So instead I dispose of the SO3 by absorbing into concentrated H2SO4, obtaining "oleum", then add water to keep the solution at 100%. To MAKE the original concentrated H2SO4 I burned sulfur to obtain SO2, absorbed the SO2 in water to obtain H2SO3, then bubbled ozonized air through the solution to oxidize it to H2SO4. An ozonizer making 4% ozone in air is not a difficult project and can be built using an automotive coil and ignition control module with a pulse circuit to fire the control module. Running at 5000 hertz the coil produces a corona discharge in air between aluminum plates separated by 1/4 inch, and insulated from each other with bathtub caulking compound around the edges. The process apparatus all runs under negative pressure using a water aspirator to pull the SO2 fumes from the burning sulfur, and the ozone from the corona discharge, into a single flask of water with both entrant tubes under the surface. I use aquarium bubble blocks on the ends of the tubes to produce fine bubbles into the water. Ozone is a powerful oxidizer, and will oxidize the H2SO3 to H2SO4. The apparatus performs without problems, and can be used to make any volume of concentrated sulfuric acid without complications. If distilled water is used in the synthesis the acid will be laboratory grade. The sulfur starting material was purchased at a garden supply, and the automotive parts at an auto store. The pulse circuit is a simple relaxation oscillator. I realize if one is not familiar with electricity or electronics making ozone the way described might be difficult, but the point to understand is that ozone, O3, will oxidize H2SO3, made by dissolving SO2 into water, into H2SO4. The apparatus as described performs without problems, and enables making concentrated sulfuric acid without any of the contamination issues other methods posted in this forum thread have.


I understand the difficulty young people have doing chemical experiments at home. When I was younger I had a few mishaps due to lack of being able to obtain proper equipment and chemicals, but fortunately survived the poison gases and small explosions long enough to learn safety first.


I suggest unless one is completely familiar with safety issues do not try this at home without supervision. If possible always best to purchase laboratory grade chemicals to begin with. I had the ozone apparatus left over from a different project used to make concentrated nitric acid, HNO3, so used it in the combustion analysis project.

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sorry about that ive just been kicked out of other forums cause of my age and am tired of getting taunted for it. and anyway i have an oxyacetelyne torch. ive been to the state science fair twice and

You will quickly consume all the oxygen in the flask and not much SO2 will be generated. I suggest you give this sciencemadness.org thread a read and try that instead: http://www.sciencemadness.org/ta

I use this method to make me CuO. Actually anhydrous cuso4 will start to decompose at about 300C. The 650 figure is the temperature at which it decomps vigorously. The so3 fumes are indeed very choking and irritating. I make it in my room without a fumehood, i just open the window :). wouldn't it be possible to condense the so3 (boiling point 45C) and then add water?


You do realize that SO3 fumes and sulfuric acid mists are considered a known human carcinogen, right?




In addition, you are probably damaging everything else in the room.

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I registered for this site today UC and have been reading the different posts about different subjects. I notice you are one of the few posters that do mention safety issues. From the description of how experiments are being conducted in many of the posts I would think some of them could be dangerous.

Since you have posted over 400 times and have read a lot more of these posts, is the lack of safety concerns always like this, or did I just drop in when no one is talking about them?

Edited by mockan
clarify point of question
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Yes, the lack of safety concern is always like this, mockan. We have a rule against what we call "HazMat" violations.. we have a lot of people that come here in attempts of playing around with substances that can REALLY hurt them, specially when they're unaware of the safety procedures that are required.


The HazMat rule is in the chemistry forum (as a "sticky"). I appreciate your comment to others to be careful with the substance you're talking about, but we don't want to subject others - who are much more at risk of harming themselves - to harmful procedures at all.


Seeing as this forum has a lot of kids and teens who come here in quest of new 'exciting' experiments to do, the concern is both ethical and legal.


Just please be aware of that for next time.


And welcome to the forum :)

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  • 3 months later...

You could take the car battery acid (a mixture of water and sulfuric acid) and distill the mixture. sulfuric acid has a boiling point of about 300 degrees Celsius, so it might work. Make sure the car battery is indeed the right type first though.


I'm not to proficient with sulfuric acid related experiments, so just an idea.

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  • 1 month later...

Couldnt you burn sulfur in to sulfur dioxide and then from there u can bubble the gas into water


That would give sulphurous acid not sulphuric acid.



passing chlorine through a solution of sulphur dioxide whould give sulphuric acid and hydrochloric acid.


If this solution is heated Hydrogen chloride gas will be formed while the sulphuric acid will remain in solution.

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Can sulfuric acid be made at home using sodium thiosulfate?


A few days ago, I extracted elemental iodine at home from tincture of iodine, HCL (31.45%, 10.3 M) and H202 (3%), then filtered and evaporated the crystals to dryness. After collecting and storing the crystals, I decided to store the dark red liquid left over (filtrate) to investigate the best way to neutralize and dispose of it. I discovered that the free iodine ions can be neutralized using sodium thiosulfate, which I had in my lab. After adding 5 g of sodium thiosulfate, the solution turned a cloudy yellow and a yellow precipitate formed on the bottom.


Researching around the web, I found that two reactions took place by the addition of the sodium thiosulfate:


1. sodium thiosulfate solution
 and HCL:

HCl + Na2S2O3 → NaCl + SO2 + S + H2O


(I did notice a yellow colored precipitate settle on the bottom of the container. I think this is probably solid sulfur mixed with NaCl).


2. sodium thiosulfate and H202 yielding sulfuric acid as a product:

Na2S2O3 + 4H2O2 → Na2SO4 + H2SO4 + 3H2O



I decided to test the cloudy, pale yellow solution with universal pH indicator paper and it turned the strip a dark red, indicating highly acidic solution.


My question is: If H2SO4 is indeed producted, how difficult would it be to filter out the solid sulfur and NaCl at the bottom, and the sodium sulfate to get the H2SO4?


Filter, collect the filtrate H2SO4, wash, then purify possibly?


Would this be a practical way of making sulfuric acid (assuming the forumulas I wrote above are correct)? Perhaps not too efficient, but sodium thiosulfate and H202 are relatively cheap, so perhaps something can be said for this method. I'd like to hear your thoughts on this way of generating sulfuric acid.

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Put stoichiometric amounts of copper and sodium bisulfate in a test tube and heat it. The following reactions will take place.

4NaHSO4 --> 2Na2S2O7 + 2H2O

2Na2S2O7 --> 2Na2SO4 + 2SO3

2SO3 + Cu --> CuSO4 + SO2

(I skipped the step where the copper is oxidized for simplicity's sake and rewrote the equation accordingly)


So the reaction produces copper(II)Sulphate and Sulfur Dioxide gas. Now you have a few options:

1) Run the SO2 through a hydrogen peroxide solution and cook it down (SO2 + H2O2 --> H2SO4)<---I did this one

2) Make a saturated copper sulfate solution and perform electrolysis with two copper electrodes

3) 2HCl + CuSO4 --> H2SO4 + CuCl2


I haven't done the second one and I don't know if the last one is even possible, but the first one definetely works :)

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  • 1 year later...

Just get some CuSO4 and make an electrolysis. With platinum anode and copper cathode. Copper deposits and rest is sulphuric acid. Boil it for more concentration. That's it, no high temps or explosions in the lab. Just electrons :)

Edited by Bob808
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  • 5 months later...

hey i head somewhere that you can make sulfuric acid from sodium bisulfate... this is pretty impure, does anyone have any other ways to make sulfuric acid or find a way to perfect this method?



It would be far easier to drain the fluid out of an old car battery - that is H2SO4

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  • 8 months later...

I'm just learning but as far as I understood it was nearly impossible to create without infinite budget. If your worried your parents won't buy sulfuric acid, they won't buy any supplies to make it because they are much more expensive.


Copper Sulfate: $1.99 at the pottery shop per pound

Electricity: Kind of depends, but a good 6V battery is usually $5-10

Carbon anodes: Just buy two 6V batteries, and take the first one apart.

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A simple sulfur-burning device composed of a large plastic tray, a small metal plate on a part of a small water bottle (to hold the plate up) to burn the sulfur on, a water bottle cut in half and placed over the metal plate and a pump to pump the oxygen in can produce large amounts of sulfur dioxide via the combustion of agricultural sulfur cheaply. Now the only thing you need to do is to oxidise it. H2O2 is the classic oxidizer, but dilute nitric acid will work as well, the NO2 produced catalysing the oxidation of SO2. If you live in a place where you can buy large amounts of low concentration H2O2 cheaply, then burning agricultural sulfur (very cheap) inside the sulfur-burner and bubbling the gases through the dilute H2O2 will produce considerable amounts of dilute H2SO4 (for a very small amount of money) that you can concentrate down by boiling.


Combining a solution of CuSO4 and oxalic acid will also work in producing H2SO4, but the reactants has to be stoichiometric, or else impurities can stuff up the final product. H2SO4 is a stronger acid than oxalic acid, but the precipitation of insoluble copper oxalate (which can be filtered out or decanted) will drive the reaction forward.

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