Sciencemadness Discussion Board - Sulphuric acid - Powered by XMB 1.9.11 (Debug Mode)

If i were to dump the nasty mixture, what would you peeps suggest to 'neutralise' the lead and acid ?

The best idea.

annaandherdad - 3-5-2014 at 14:14

If you can't find sulfuric acid on the forum, try spelling it "sulfuric" instead of "sulphuric". Also, google works better than the forum search engine, include "sciencemadness" in your search.

It was a mistake to play with this stuff out of old batteries. Now you have an acidic mess of poisonous lead compounds. There is nothing you can do to make the lead less poisonous, but with some effort you could precipitate it as a carbonate or other insoluble salt, which would be better than something soluble. You'll have to get rid of it some place where they take lead. Maybe you could just pour the gunk back into old battery cases and take them to a battery recycling center.

You can't concentrate sulfuric acid by boiling it, at least it's not practical at home. This has been covered on the forum elsewhere.

Manifest - 3-5-2014 at 15:08

How can you not concentrate by boiling?
I have done it before with success.

blogfast25 - 4-5-2014 at 05:18

Quote: Originally posted by annaandherdad

There is nothing you can do to make the lead less poisonous, but with some effort you could precipitate it as a carbonate or other insoluble salt, which would be better than something soluble.

Brilliant! Let's create loads of bubbles and froth by neutralising fairly concentrated sulphuric acid with sodium carbonate!

No. Just pour the mess back into the battery if possible and dispose of it as you should.

unionised - 4-5-2014 at 05:52

May I invite you all to consider briefly how a car battery works?

Given that the plates in a discharged battery are made of lead sulphate and sitting in a solution of sulphuric acid, how soluble do you think lead sulphate is in those circumstances?

So "with some effort you could precipitate it as a carbonate or other insoluble salt"
Did anyone consider the sulphate as such a salt?

(Granted, the carbonate is about ten times less soluble).

Having said that, "Just pour the mess back into the battery if possible and dispose of it as you should. " is probably the best advice so far.

HgDinis25 - 4-5-2014 at 06:14

Lead Sulfate isn't that giant scary beast that will poison you just by looking at it. It is fairly insoluble in water.

If you can't put everything back into the battery, I suggest you dilute your sulfuric acid and then add enough NaOH to neutralize it. Then add more NaOH to neutralise any soluble Lead ions still present. This will make Lead Oxide, more or less harmless.

To any other solutions that may contain soluble Lead Ions, add NaOH too. Then, you can simply filter everything and discard your aquous phase. Then put your insoluble Lead crap and stuff it into a ZIP bag, stuffed in another ZIP bag that has been stufed in yet another ZIP bag. Then garbage.

unionised - 4-5-2014 at 09:55

Do bear in mind that lead sulphate is reasonably soluble in sodium hydroxide solution.

aga - 4-5-2014 at 11:17

Concentrated Lead/Sulphuric mess all back in the battery, and goes for recycling tomorrow.
Another dead-end, but learning all the way.
The colours, and the changes thereof, are beautiful.

Same as my recent neodymium extraction : i now have beautiful pale violet iron III sulphate paste.

@Manifest : I was also surprised at the comment:-
"You can't concentrate sulfuric acid by boiling it, at least it's not practical at home"

@Annaandherdad : presumably you're saying to NOT do this in a home kitchen, with which i wholly agree.

Doing 250ml on a temperature controlled hotplate in a borosilicate vessel, in a fume hood, with a silicon sealed glass-trough base should be OK ?

blogfast25 - 4-5-2014 at 11:21

Here's a decent 'how to?' on the subject. Jeffrey used to hang out here sometimes.

http://amazingrust.com/Experiments/how_to/Concentrating_H2SO...

IrC - 4-5-2014 at 13:38

Here's a decent 'how to?' on the subject. Jeffrey used to hang out here sometimes.

http://amazingrust.com/Experiments/how_to/Concentrating_H2SO...

Thank you for that link, never found this site before. He has a great page on making Bismuth crystals, a hobby of mine.

S.C. Wack - 4-5-2014 at 14:38

If you're producing fumes like that link does, you're not concentrating the acid...as I've said before the fumes seem to be the result of atmospheric water, like the hot acid wants it so bad that it'll jump right out of the flask for it...

hissingnoise - 5-5-2014 at 05:46

Quote:

If you're producing fumes like that link does, you're not concentrating the acid...

That fuming does actually lead to 98% H₂SO₄!
My first attempt filled the open shed I used with a choking vapour . . .
And I've used the procedure several times, since!

blogfast25 - 5-5-2014 at 06:01

If you're producing fumes like that link does, you're not concentrating the acid...as I've said before the fumes seem to be the result of atmospheric water, like the hot acid wants it so bad that it'll jump right out of the flask for it...

How can he NOT be concentrating acid when the volume is decreasing and the BP of water is much lower than that of pure H2SO4?

Hot acid jumping out of the flask to grab water???? Explain?

@IrC: thanks. He has some interesting stuff.

[Edited on 5-5-2014 by blogfast25]

Manifest - 5-5-2014 at 08:59

Aga, you quoted wrong, I defended boiling acid to concentrate it.

Etaoin Shrdlu - 5-5-2014 at 10:09

He is concentrating the acid, it's just that some sulfuric acid comes off along with the water at higher concentrations, there's no sharp divide at 98% purity where sulfuric acid finally obtains a vapor pressure...

S.C. Wack - 5-5-2014 at 10:58

I don't see how one can think that losing SOx is concentrating the acid. It would not surprise me if some other chemical is formed when this is lost.

If done out of contact of air, only water comes off. Move the hot acid to air, the S something comes right out.

hissingnoise - 5-5-2014 at 11:59

Quote:

I don't see how one can think that losing SOx is concentrating the acid.

Negligible SO_x is lost in process and it was widely employed by nitration plants in the past . . .
Today's SACs run under reduced pressure but the principle's the same!

aga - 5-5-2014 at 14:44

I don't see how one can think that losing SOx is concentrating the acid

I'm a total noob, but even to me it seems obvious that if you drive off more Water than SOx then the remaining solution will be stronger : less water in the mix.

Are the 'fumes' connected with water vapor and SO₃ going *pop* bigtime ?

S.C. Wack - 5-5-2014 at 15:05

Quote: Originally posted by hissingnoise

Negligible SO_x is lost in process and it was widely employed by nitration plants in the past . . .

Did they heat an open vat of sulfuric acid over a fire in the woods? Do it and tell me that negligible amounts are being lost.

You cannot say that more water is being lost if you don't know. I do not say this without having concentrated many gallons of battery acid from Lowe's. There is a point I stop.

[Edited on 5-5-2014 by S.C. Wack]

Etaoin Shrdlu - 5-5-2014 at 15:21

We do know more water is being lost. The azeotrope is ~98% in water. That is the point at which sulfuric acid starts coming off at the same rate as water when the solution is boiled. Before that, more water is coming off than sulfuric acid.

http://books.google.com/books?id=Mtth5g59dEIC&pg=PA546&a...

I've never seen this disputed before. I assume from your experience concentrating many gallons of battery acid that you have data which would demonstrate otherwise?

S.C. Wack - 5-5-2014 at 19:38

The azeotrope has nothing to do with fuming in air, and neither do vapor pressure measurements not involving undried open air. There is a clear point in the 80's percent where fuming from hot open containers exposed to moist air becomes an issue.

Needless to say, obtaining vapor pressure measurements in such a situation is troublesome.

[Edited on 6-5-2014 by S.C. Wack]

Etaoin Shrdlu - 5-5-2014 at 20:20

We all know azeotropes have nothing to do with fuming. The question is why in the devil you think fuming means more sulfuric acid is coming off the mixture than water.

S.C. Wack - 5-5-2014 at 20:40

If you tried it, you'd know the extent of the fuming.

hissingnoise - 6-5-2014 at 09:36

Quote:

Did they heat an open vat of sulfuric acid over a fire in the woods? Do it and tell me that negligible amounts are being lost.

Indeed they did, though not in the woods . . . ?
Acid was boiled in silicon-iron pots (Pauling process) suspended above a furnace!
Occasional catastrophic failure of the pots due to poor heat-transfer of the alloy led to boiling acid entering the furnace and the method was largely superseded by the Simonson-Mantius process which could be run under vacuum . . .

Etaoin Shrdlu - 6-5-2014 at 09:42

If you knew yourself, you'd be telling us what said extent was instead of continually repeating an assumption based on visual assessment.

Don't act as though measuring vapor pressures has anything to do with it either. You could demonstrate your point very easily by boiling dilute sulfuric acid, taking occasional samples, and showing that the pH stops dropping around 80% or whatever your cutoff point was.

Otherwise, theres really no reason to believe you over every reliable reference that says distilling sulfuric acid is a great way to concentrate to 98%, and I quote, "An acid with the same composition and boiling point is obtained when dilute sulfuric acid is distilled, since in this case the first distillate is almost pure water."

EDIT: You know, since you're just going to bring up the air thing again, the amount of water air can hold at any boiling point of a sulfuric acid/water solution at atmospheric pressure is staggeringly higher than the amount of water air can hold at any reasonable room temperature. The effect of your relative humidity should be pretty much zilch unless you're living on Venus.

[Edited on 5-6-2014 by Etaoin Shrdlu]

aga - 6-5-2014 at 11:47

OK. I feel the need t Moderate, seeing as it's going South about now ...

Sulphuric acid can be concentrated by boiling.

The water leaves a lot faster than the SO_x at lower temperatures.

When Fumes are seen, *something* has started to happen : water is not the only thing leaving.

Stop boiling about the point that the Heavy Fumes are seen, and that's as good as the concentration will be if judged by eye alone.

H₂SO₄ probably behaves in a much more complicated way, however, you boil a dilute solution of the acid, and it gets less dilute : i.e. stronger solution.

Whichever way you cut it, boiling works.

[Edited on 6-5-2014 by aga]

[Edited on 6-5-2014 by aga]

blogfast25 - 6-5-2014 at 12:21

Someone here is going to have to bite the bullet and determine experimentally what max. concentration H2SO4 can be obtained with this (atmospheric) open vessel boiling in of dilute H2SO4 solutions.

My money is on 95 w% or slightly better.

[Edited on 6-5-2014 by blogfast25]

Zyklon-A - 6-5-2014 at 12:25

I've heard 98.3% is the absolute highest possible to reach by boiling, but I bet yields are terrible.

aga - 6-5-2014 at 12:40

Quote: Originally posted by Zyklonb

I've heard 98.3% is the absolute highest possible to reach by boiling, but I bet yields are terrible.

Excellent. First Takers.

ZyklonB has $50 on 98.3%
Blogfast25 has $50 on 95%

Place your bets people.

I will be doing the titration, so the result will be pretty much random.

S.C. Wack - 6-5-2014 at 12:44

Quote: Originally posted by Etaoin Shrdlu

Otherwise, theres really no reason to believe you over every reliable reference that says distilling sulfuric acid is a great way to concentrate to 98%, and I quote, "An acid with the same composition and boiling point is obtained when dilute sulfuric acid is distilled, since in this case the first distillate is almost pure water."

Where did I say anything about distilling? You seem more interested in trolling than in what is actually happening; take your straw man elsewhere.

Sulfuric acid leaves the open flask in a most obvious way, regardless of whether you say it doesn't. The fumes do not come off in a small amount once a certain temperature is reached. Less fumes are produced when the surface of the acid is less open to the air, it's obvious if you do it. It is foolish to continue heating at that level of fuming, because those fumes are not water.

Quote: Originally posted by hissingnoise

Indeed they did, though not in the woods . . . ?
Acid was boiled in silicon-iron pots (Pauling process) suspended above a furnace!

Have I been talking about this sort of apparatus, or, something like the fuming flask in the link? This is an "open vat"?

Attachment: DE299774C.pdf (192kB)
This file has been downloaded 396 times

HgDinis25 - 6-5-2014 at 12:50

S.C. Wack, boiling Sulfuric Acid is effective uo to 70% concentration. Past that, fumes will start forming. However it is completly possible to reach 98% concentration, at 300ºC.
I've never realy seen anyone arguing about this.
Anyway, here's some proof:
http://www.youtube.com/watch?v=okvvD3-DF9U

blogfast25 - 6-5-2014 at 13:20

Anyway, here's some proof

As far as evidence goes, it's fairly weak. The concentration of the obtained acid wasn't measured.

aga - 6-5-2014 at 13:35

Hahahaha

My sulphuric acid gets concentrated by boiling.
Tested by experimentation.

Seems that You all start Fuming at much lower temperatures !

Being a Noob is a Bonus right now : i don't think i Know enough to think i'm Right, to the exclusion of all else.

Watching Experts is certainly amusing.

[Edited on 6-5-2014 by aga]

HgDinis25 - 6-5-2014 at 13:41

Anyway, here's some proof

As far as evidence goes, it's fairly weak. The concentration of the obtained acid wasn't measured.

Actualy, it's more a proof of persona, if you get where I'm going...

Zyklon-A - 6-5-2014 at 14:18

I've never realy seen anyone arguing about this.
Anyway, here's some proof:
http://www.youtube.com/watch?v=okvvD3-DF9U

Boiling dilute sulfuric acid to concentrate it is common knowledge, I've never seen anyone argue this either.
That's not proof, he never tested the concentration - it could be water for all anyone knows. (Although I trust Nurdrage.)

Excellent. First Takers.

ZyklonB has $50 on 98.3%
Blogfast25 has $50 on 95%

Place your bets people.

I will be doing the titration, so the result will be pretty much random.

I'm not putting a penny on your titration setup unless I see it!

HgDinis25 - 6-5-2014 at 14:27

Zyklonb, like I said, proof of persona.

Etaoin Shrdlu - 6-5-2014 at 15:37

Where did I say anything about distilling? You seem more interested in trolling than in what is actually happening; take your straw man elsewhere.

I thought it was common knowledge that boiling while collecting the vapors leaves the same result in the flask as boiling without collecting the vapors. Straw man? Trolling? Are you referring to yourself?

EDIT: Or have we discovered a macroscale uncertainty principle?

Sulfuric acid leaves the open flask in a most obvious way, regardless of whether you say it doesn't.

Again, referring to yourself? Everyone so far has readily admitted it does leave the flask.

The fumes do not come off in a small amount once a certain temperature is reached. Less fumes are produced when the surface of the acid is less open to the air, it's obvious if you do it.

Increasing the area of the interface is not going to affect the dynamics at that interface. Boiling sulfuric acid in a pan versus a long-necked flask is just going to concentrate it faster, the same vapors should come off unless you're recondensing the sulfuric acid somehow or there's something really significant and interesting about the way the system is interacting with the atmosphere, that nobody's described yet. Write a paper?

All anyone's saying is that it's definitely possible to concentrate sulfuric acid by boiling (and I'm also saying there's no reason to think it will jump out of the flask after water vapor to any significant extent, mentally provocative as the thought is).

The last graph here may be of interest. It is the only one of its kind I can locate right now. The vapor concentration of sulfuric acid climbs significantly between 90-98%.

http://www.akersolutions.com/Documents/PandC/Mining%20and%20...

Aga, my money's on 98%...to that many significant figures.

[Edited on 5-6-2014 by Etaoin Shrdlu]

blogfast25 - 7-5-2014 at 04:27

Zyklonb, like I said, proof of persona.

Proof of persona??? Inventing new types of 'evidence' won't get us out of this pickle.

At the end of the day those who make claims of > 95 % (like NR) should back them up with actual evidence. He didn't do that. The sugar dehydration doesn't prove actual concentration either, only that it must be quite high.

Time allowing, I might have a stab at this...

Fantasma4500 - 7-5-2014 at 05:17

boiling point could be checked to confirm that you would be capable of reaching higher temperatures, i recall that 300*C is the target if you want 96-98% H2SO4
what to measure it with -- thats another question..

but i would suggest that the SO3 coming off the boiling H2SO4/water mixture would also drag some water with it at the same time

also a shed is not a real problem, being more than just new to chemistry and attempting to boil it down in a steel pot on a gas flame and fogging up an 12 room big house -- thats a difference case
nothing is so bad that its not good for something -- im sure most bacterias in that house was wiped away that day, at least surface bacterias

however.. NH4OH solution could be put next to it to remove the SO3 fumes

hissingnoise - 7-5-2014 at 08:57

Quote:

. . . also a shed is not a real problem, being more than just new to chemistry and attempting to boil it down in a steel pot on a gas flame and fogging up an 12 room big house.

Jeeez! That sure stimulates my cough reflex ─ 'hope your soft furnishings remain unaffected . . .

blogfast25 - 7-5-2014 at 09:12

I like this bit:

Quote: Originally posted by Antiswat

however.. NH4OH solution could be put next to it to remove the SO3 fumes

If you can't gas them with H2SO4 off gases, try ammonia!

Do you run a 'little chemical house of horrors', or something?

blogfast25 - 7-5-2014 at 10:17

I've just checked my hot plate and it creeps slowly up to 300 C, hot enough for 95 % H2SO4 ('in theory'), so I'm actually going to boil down about 20 ml of 70w% H2SO4 to as far as I can bear it. And determine acid strength by titrometry. Need some decent weather though, right now it's threatening to rain...

aga - 7-5-2014 at 11:26

What is this 'rain' that you speak of ?

Is it an element ?

Where can i buy some ?

HgDinis25 - 7-5-2014 at 11:45

blogfast25, are you kidding me? Inventing new kinds of evidence?

Let me ask you, if you have two people, one is defending hypothesis A and the other is defending hypothesis B. You don't have a way to check it by yourself. Then comes a very respeced person, specialized in the field, that says that hypothesis A is the correct one. It, however, only gives a brief explanation. Are you saying that, in your mind, hypothesis A wouldn't get a few points of consideration, perhaps making you considering it as true?

blogfast25 - 7-5-2014 at 12:48

HgDinis25:

You're making several reasoning errors:

1) NR isn't 'specialised in the field'. He carried out the experiment but didn't provide evidence for the 95 + assertion.

2) Experts get things wrong too. There's a term for invoking experts: 'appeal to authority fallacy'.

3) That A would get a few points of consideration would only tell of my credulity, not that A is actually true. It's not about 'considering it as true' but whether it IS true or NOT.

And what constitutes an 'expert': why is NR more of an expert (in your eyes) than SCWack?

aga:

I'll send you some but it'll cost you! And it might be a bit acidic too...

[Edited on 7-5-2014 by blogfast25]

HgDinis25 - 7-5-2014 at 12:57

HgDinis25:

You're making several reasoning errors:

1) NR isn't 'specialised in the field'. He carried out the experiment but didn't provide evidence for the 95 + assertion.

2) Experts get things wrong too. There's a term for invoking experts: 'appeal to authority fallacy'.

3) That A would get a few points of consideration would only tell of my credulity, not that A is actually true. It's not about 'considering it as true' but whether it IS true or NOT.

aga:

I'll send you some but it'll cost you! And it might be a bit acidic too...

Actually, there's this thing called the Authority Argument. It isn't always a fallacy. Since you brought it up, let me explain something to you.
In order to be valid, an Authority Argument must comply to the following requirements:
- The specialist must indeed be a specialist in the given field;
- There mustn't be controversy between specialists;
- The specialist mustn't have personal interestes;
- The argument mustn't be weaker than a refuting argument.

The video of nurdrage comply to the four requirements, in my personal view.

I do, however, agree that withou evidence, we can't really be that 100% sure, and that "experts" do get things wrong. However, it is still an argument. And when two points are being discussed, it is of importance to use. I'm not saying that it has the same importance as an experimental proof argument, I'm saying that it has some importance.

aga - 7-5-2014 at 13:05

Let me ask you, if you have two people, one is defending hypothesis A and the other is defending hypothesis B. You don't have a way to check it by yourself. Then comes a very respeced person, specialized in the field, that says that hypothesis A is the correct one

My response to that situation would be that I Don't Know.

If i had to Act with that information, i would set teams 1,2,3 down route A, and team 4 on route B.

Team 5 would be set to find out if there were another possibility, which did not rely on routes A or B.

'Follow the Leader' seems OK, but doesn't do Lemmings much good.

HgDinis25 - 7-5-2014 at 13:07

haha I love your team routes example. I was thinking pretty much like that when I was writing the thing.

blogfast25 - 8-5-2014 at 05:00

The video of nurdrage comply to the four requirements, in my personal view.

"[...] in my personal view."

Says it all: i.o.w. it's a belief system.

Testimony by people like NR is a form of evidence but it's rather weak because he provides no proof of his assertion.

[Edited on 8-5-2014 by blogfast25]

blogfast25 - 8-5-2014 at 08:49

Here’s the first part of my experiment.

12 g of water and 28 g (15 ml) of conc. H2SO4 were loaded into wide necked 200 ml Erlenmeyer. This makes a concentration of about 70 w%. Both the flask and its content were weighed to 0.1 g.

The flask was then heated on an electrical plate on maximum setting (about 300 C):

Boling started shortly after start of heating and was gentle and without fuming. Clearly steam was coming off.

5 minutes (measured) later boiling had ceased altogether and the first fumes started coming off, at first only lightly:

Fumes became thicker and thicker though. It’s clear that without fume hood this cannot be done safely inside: the furmes are very choking.

And then it started raining, at first almost nothing, so I got a large umbrella to protect the experiment and hoping to weather it but then a bit more, and more, you get the picture. So for electrical reasons the run had to be stopped, about 25 minutes into it.

I allowed the flask to cool down to about 70 C, then weighed it: it had lost 14.6 g weight.

The flask has now been covered with quadruple cling film, ready for titration, hopefully tomorrow.

CHRIS25 - 8-5-2014 at 08:56

(you've got weeds on your patio)

Zyklon-A - 8-5-2014 at 09:01

I've just checked my hot plate and it creeps slowly up to 300 C, hot enough for 95 % H2SO4 ('in theory').

Maybe, but 300°C isn't really enough if we want to see what the highest concentration possible is by boiling.
I guess I could give it a go. My hot plate get over 460°C in ~ 5 minutes.
I can almost melt aluminum on it, the highest it can get is about 620-640°C.

[Edited on 8-5-2014 by Zyklonb]

blogfast25 - 8-5-2014 at 09:37

Zb:

From Wiki:

Boiling point: 337 °C (639 °F; 610 K) When sulfuric acid is above 300 °C (572 °F), it will decompose slowly

Although nearly 99% sulfuric acid can be made, the subsequent loss of SO3 at the boiling point brings the concentration to 98.3% acid. The 98% grade is more stable in storage, and is the usual form of what is described as "concentrated sulfuric acid." Other concentrations are used for different purposes.

Trust me, if you'd seen what I’ve seen (and smelled!) you really don’t want to go much above 300 C. Destroying part of the acid to get an extra 1 % is folly. These super high concentrations are achieved via Oleum I believe.

By all means have a shot. But only if you can measure final concentration… otherwise it will only contribute to the general confusion and disagreement.

C25:

It's no laughing matter! Damn nuisance, weeds...

[Edited on 8-5-2014 by blogfast25]

HgDinis25 - 8-5-2014 at 10:10

The video of nurdrage comply to the four requirements, in my personal view.

All knowledge is beliefe. In your last sentence you defendend my point.

blogfast25 - 8-5-2014 at 11:24

All knowledge is beliefe.

But some beliefs are superior to others. Evidence based belief systems are better than faith based belief systems.

[Edited on 8-5-2014 by blogfast25]

blogfast25 - 8-5-2014 at 11:32

The titration results are in.

About 1 g of the concentrated acid was weighed accurately and diluted to 250.0 ml in a volumetric flask.

Three 20.0 ml pipetted aliquots were titrated with 0.1 N NaOH of known titre, using phenolphtalein as indicator. Three identical titration volumes were obtained and calculated to 97.4 w% H2SO4.

A simple density determination (using a 10.0 ml measuring cylinder and 0.01 g scales) gave a density value of 1.84, in accordance with the % value.

So it appears that concentrating dilute H2SO4 by open kettle boiling is possible to at least 95 – 97 w% (allowing for measuring error). I don't know whether even higher values can be achieved.

I think in practical terms one can stop perhaps 15 – 30 minutes after fuming starts, to get that indicated range of w% H2SO4.

[Edited on 8-5-2014 by blogfast25]

HgDinis25 - 8-5-2014 at 11:50

blogfast25, Of course, evidence based beliefes are what I believe we all follow here.

Nice report. Now we have the proof. But let me ask you the following, and please don't take this personally. I'm just stating an hypothesis, one I believe almost false, so don't take this in the wrong way.

How does that post of yours serve as proof? We don't know if you're telling the truth or not. You don't state explanations you are merely discribing facts. People can lie about facts. How is your post any different from Nurdrage's video? We believe in you because you are seen as an "expert" in the fiel and as trustworthy. So, wouldn't your report be in the same level as Nurdrage's video?

Now leaving matters aside, I think it has been well established that concentrating Sulfuric Acid works by this method.

blogfast25 - 8-5-2014 at 12:08

HgDinis25

Nice comments that go to the heart of what is evidence and what is proof.

The answer is simple. I provided an experimental set up that anyone can follow and replicate. I'm fully confident that any bona fide experimenter will find as I found.

In short, you don't have to believe me but should perform your own experiment to prove me wrong, should you be that way inclined. That's how it works. No offence taken. Skepticism is at the heart of the scientific method.

The experiment would gain much in value by others confirming its results, independently.

[Edited on 8-5-2014 by blogfast25]

HgDinis25 - 8-5-2014 at 12:14

blogfast25, Indeed the main difference is that you give an experimental setup that can prove your hypothesis. We can only get "real" proof (and I say "real" because defining what's real proof isn't as simple as it migh appear) when experimenting or seing an experiment and then theorize an explanation (or the other way around). That's how Synthetic a Priori Judgment works, the basis of science.

S.C. Wack - 8-5-2014 at 13:58

How much of the missing 2.6 grams was sulfuric acid? Recall that what started all this before y'all turned it into something else is the fumes.

[Edited on 8-5-2014 by S.C. Wack]

aga - 8-5-2014 at 14:06

Goats.

What you really need for weeds is Goats.

I'll give this a try tomorrow with the lead sulphate + SiC contaminated acid i got.

Do you use an erlenmeyer rather than a straight beaker in order to try to 'keep' some SO_x in the pot ?

I'll try it with a conical flask, a straight beaker and an open tapered pot (pyrex measuring jug) and see if it makes any difference.

Why can't some (if not all) of the SO_x be directed back through the boiling liquid ?

Would that not raise the resulting conc. even if by just a little ?

[Edited on 8-5-2014 by aga]

HgDinis25 - 8-5-2014 at 14:38

aga, problem is seperating the Sulfur Oxides from the water. Condensing is not an option because the gases would dissolve in the water condensing.

aga - 8-5-2014 at 15:53

You're right.
I've just been pondering on what SO₂ and SO₃ actually *do* in the water vapour.

First thought is fractionation, but still pondering.

I kinda agree with SC Wack's point that SO_x is lost - seems wasteful and crude.

[Edited on 8-5-2014 by aga]

blogfast25 - 9-5-2014 at 04:26

How much of the missing 2.6 grams was sulfuric acid? Recall that what started all this before y'all turned it into something else is the fumes.

[Edited on 8-5-2014 by S.C. Wack]

How am I supposed to know that? At a guess: 100 %.

WE have turned this into something else??? See, I kind of expected that response from you. Read the thread again and stop trying to back pedal: you lost this argument, plain and simple. It was your (justified) scepticism among other things that made me run the experiment. It turns out that concentrating dilute H2SO4 to 95 - 98 w% with open pot boiling is not problematic, as stated by plenty 'how to?' guides.

Aga: the Erlenmeyer shape somewhat prevents splattering droplets from the boil leaving the flask. That's why I chose it over a plain beaker. A beaker covered with an hour glass or similar would have been better but a bit slower.

[Edited on 9-5-2014 by blogfast25]

Zyklon-A - 9-5-2014 at 07:49

What about electrolysis of concentrated sulfuric acid to make it anhydrous? Has anyone tried this? Pulverulescent wanted to try this as another rout to oleum in len1's Sulphur Trioxide and Oleum guide.

Quote: Originally posted by Pulverulescent

I'm not discarding my ancient idea of trying to electrolyse H₂S0₄ to remove H₂0 to the point where oleum is produced, though.

Well, not unless someone's found insurmountable obstacles to that process!
And I have an inert anode!

P

I'm guessing Pt is required as an anode. Whether or not this will produce oleum, I don't know, but it seems like it could work fine for producing 100% H₂SO₄.

S.C. Wack - 9-5-2014 at 11:44

WE have turned this into something else??? See, I kind of expected that response from you. Read the thread again and stop trying to back pedal: you lost this argument, plain and simple.

I haven't been talking through the straw man you and the troll have been building. You're just trying to find a response to the benzene thread. The troll on the other hand has no excuse.

Actually, that's the response I expected from you. Go ahead and post exactly which statement/argument I made that you've proved wrong.

[Edited on 9-5-2014 by S.C. Wack]

blogfast25 - 9-5-2014 at 11:55

I haven't been talking through the straw man you and the troll have been building. You're just trying to find a response to the benzene thread. The troll on the other hand has no excuse.

What on Earth are you taking about now? The benzene thread??? What does this have to do with anything here?

In which way am I "trying to find a response to the benzene thread"? What you claim is ABSURD, Sir.

Troll? I don't see one. But I do see a twit... and not for the first time either.

[Edited on 9-5-2014 by blogfast25]

HgDinis25 - 9-5-2014 at 12:28

Dear S.C. Wack,

Quote:

you're not concentrating the acid, blogfast proved you wrong in this.

Quote:

The azeotrope has nothing to do with fuming in air, and neither do vapor pressure measurements not involving undried open air. There is a clear point in the 80's percent where fuming from hot open containers exposed to moist air becomes an issue.

He got it to past 95% so, again, there isn't enough SO_x vapors coming out so as to not concentrate the acid.

Quote:

You cannot say that more water is being lost if you don't know. I do not say this without having concentrated many gallons of battery acid from Lowe's. There is a point I stop.

Now we know that more water is being lost.

You're overreacting to this. You we're wrong, so what? Like Karl Popper stated once, you should be celebrating right now. Thanks to your error we're now closer to the " truht", we now know something new. No shame in it, we're all wrong from time to time.

aga - 9-5-2014 at 12:39

I was wrong once, i think. Maybe i'm wrong about that.

Hero worship is not such a bad thing.
NurdRage is excellent, amusing, and highly inspirational.
The videos are great !

Science is a different thing though, and blogfast25 has done the experiment, demonstrated the method and the shown results in a way that can be repeated and checked (measured everything relevant) and is the deserving winner of the Banana of Truth.

S C Wack may not be as highly Gruntled with the result, however the point raised regarding the Loss of SO_x in the process is worthy of some thought, as there is obviously some loss.

Simply piping the vapours through H₂O perhaps, or use a Vigreux to better separate the phases ...
I'm a noob, so there's probably obvious reasons why neither would work.

aga - 9-5-2014 at 12:41

benzene thread.

Wierd. i have been looking for that thread since about 20 mins ago.

blogfast25 - 9-5-2014 at 13:01

Simply piping the vapours through H₂O perhaps, or use a Vigreux to better separate the phases ...

Go upstairs and look for the file SC linked too: it shows you the kind of apparatus needed to recover the fumes. My German is just 10 - 15 % short of fully understanding the text though.

aga - 9-5-2014 at 13:09

Danke.
Meine Deutche ist auch noch nicht gut genug, aber ich kann arbeiter.

macckone - 9-5-2014 at 18:06

Quote: Originally posted by Zyklonb

What about electrolysis of concentrated sulfuric acid to make it anhydrous? Has anyone tried this? Pulverulescent wanted to try this as another rout to oleum in len1's Sulphur Trioxide and Oleum guide.

Quote: Originally posted by Pulverulescent

I'm guessing Pt is required as an anode. Whether or not this will produce oleum, I don't know, but it seems like it could work fine for producing 100% H₂SO₄.

This is the method to peroxydisulfuric acid.
Not that wiki is the most reliable but:
http://en.wikipedia.org/wiki/Peroxydisulfuric_acid

You can also look for A.J. Hale, The Manufacture of Chemicals
by Electrolysis which has an in depth discussion.
https://archive.org/details/manufactureofche00halerich

Zyklon-A - 10-5-2014 at 11:56

Ok, thanks. The Simad library has that book too:http://library.sciencemadness.org/library/books/the_manufact...

S.C. Wack - 11-5-2014 at 09:14

Dear S.C. Wack,
you're not concentrating the acid

Did I say that you can't concentrate, say, once you see fumes like in the first picture, or do any of you have any sense? Is If you're producing fumes like that link does at the end, you're not concentrating the acid, you're just fuming it off good enough for you?

blogfast25 - 11-5-2014 at 09:47

We don't know at which concentration precisely the fuming starts. So how do we know that when it starts water is no longer coming off at a rate higher than the acid coming off or decomposing? If water is still coming of faster than you lose acid, you're still concentrating, albeit wastefully.

Maybe in a future experiment I'll take samples at various points: start of fuming, 10 minutes in, 20 minutes in, etc, to evaluate concentration.

aga - 11-5-2014 at 15:37

OK.

Enough is enough.

There is only 1 way to settle this - FIIIIGHT !

S C Wack vs Blogfast25

Normal chem fight rules : Method, Experiment, Results, Conclusion.

First one to (verifiable) 98.9% conc. wins.

[Edited on 12-5-2014 by aga]

blogfast25 - 12-5-2014 at 04:55

Aga:

You watch too much Harry Hill...

aga - 18-5-2014 at 14:55

This should not have been a surprise, but it actually IS !

Currently i'm boiling down 400ml Brown drain cleaner (says 75% Acido Sulfurico on the label) to which i have added 20% by volume of 3% OTC H₂O₂ which has removed the Brown stuff.

At least the solution is Clear now.
Whether the acid will end up Pure is unknown.

Due to Other Things To Do, i have heated/stopped 3 times today.

When i got back to the 'Lab' (such as it is) the liquid levels were 25ml lower than when i switched off the hotplate, and left them to cool (approx 3 hours ago).
A Small Fan is running to help remove the water vapour.

So, i restarted the heating, typed stuff on this website etc, then looked again at the acid (~20 mins)

Liquid levels are back to where i left them, now that the temperature is 180 C ! 25ml just reappeared !

A quick look around to see if there was a grass snake with a wash bottle showed that nothing External had happened.

So, when removing water from Sulphuric Acid by heating/evaporation, the temperature at which Volume is measured is vitally important.

This may not be anything at all to most people here, but it surprised me.

[Edited on 18-5-2014 by aga]

blogfast25 - 19-5-2014 at 05:11

aga: just try and boil it down until it starts fuming. My guess is that will give you 95 w% H2SO4 or slightly better.

Nice idea with the peroxide. Might have been better to test on small scale though, to see just how much peroxide you need to oxidise the brown stuff away...

aga - 19-5-2014 at 05:43

Might have been better to test on small scale though

Funnily enough, the 40ml beaker needs cleaning

[Edited on 19-5-2014 by aga]

blogfast25 - 19-5-2014 at 09:03

Please also bear in mind that you should avoid pouring water (or watery solutions) into concentrated sulphuric acid because it can splatter badly. If you have to (here you had no choice) do it slowly and with constant stirring.

The acid was only 75 % so it wasn't as dangerous but with 98 % this is really not recommended. You should always (where possible) add the acid to water, not the other way around.

aga - 19-5-2014 at 13:45

Good advice.

I seem to remember that one from way back, so the stirbar was spinning, and the H2O2 went in drop by drop into the cool acid (wasn't cool for long !).

It still wanted to spit and fizzle though, which is where gloves, full-face visor and a fume hood all seemed less than overkill.

Just for kicks i thought i'd see what pH the solution registered on a UI paper strip.
The colour chart doesn't give a reading for Instantly Blackened and totally Dissolved with a pfzzzt sound.

The fume hood fan was upgraded from a PC fan to a 230v extractor at the suggestion of an SM member, and that came in handy today.

[Edited on 19-5-2014 by aga]

blogfast25 - 20-5-2014 at 04:57

50 % is enough to destroy ordinary paper.

aga - 20-5-2014 at 13:45

These rubber gloves seem OK with sulphuric acid - not that i've actually tested that theory to destruction.

Presumably there are substances which would destroy rubber gloves instantly.

Are there any Guidelines that should be known, such as neoprene, natural rubber, nitrile etc when dealing with certain chemicals ?

macckone - 20-5-2014 at 18:32