What type of container, besides glass, will safely hold concentrated sulfuric acid without the stuff eating through it? I got to wondering about that after finding out how to make the stuff much stronger than what goes into car batteries. I’ve always found it in glass bottles with ground glass stoppers over the years but batteries, to my knowledge, are simply heavy plastic, even though the sulfuric acid, while strong, is not industrial strength.
It’s obvious that nothing with a metal screw on lid will work.
That’s not quite true, pure gold doesn’t react with concentrated sulfuric acid.
I’m sure some ceramics will work; I’ve seen ceramic flasks used to store HF, an acid which dissolves glass. Plastics generally aren’t very reactive to acids. I’m not sure exactly which plastic is used in car batteries.
HF doesn’t simply dissolve glass, it reacts quite violently with it. It is correct that it is often stored in ceramic vessels, although can, IIRC (I really could be wrong here), be stored in nickel containers.
As mentioned, most polymers/plastics are pretty unreactive towards acids; oleum, concentrated sulphuric acid saturated with sulphur trioxide reacts only slowly with plastics.
Not something I’d advise, because it will hurt eventually, but you’d be surprised how little damage short term exposure to conc. sulphuric acid does…wash it off after a few seconds and it just discolours your skin a little, but leave it on for a while and you get these horrible blisters which take forever to heal. Not nice.
IIRC they used to store HF in bottles lined with wax. Nowadays I think they use plastic, although I don’t know what sort. I’d be willing to bet that teflon doesn’t react with it, but good luck finding a teflon bottle. (I’ll bet that you could find or make teflon seals for your lids, though). Check and see what kind of bottles the chemical companies use (Fisher Scientific or Alfa or Aldrich).
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You’re right. Teflon doesn’t react with HF, and has been used to handle it for some time. (My reference is dated 1986, and from context it’s clear that it had already been used for a while)
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Car batteries, IIRC, are about 6 molar sulfuric acid while concentrated is 18. (Again, IIRC)**
AWB** wrote:
Well, I thought it was about what to put it in. To answer your question: for car batteries, put two electrodes (composed of PbO/H2SO4 supported by an inactive grid, with more Pb in one and more PbO2 in the other) and some water in it.
I recall my high school chemistry teacher telling us that pure sulfuric acid could be safely stored in metal containers, as long as no water could get in. The corrosive qualities of acid come from its ability to produce hydrogen ions when mixed with water. Pure acid -> no reaction with water -> no hydrogen ions -> no corrosion.
Of course, this was a long time ago and I majored in history in college, so please let me know if I’m full of it.
Well, I haven’t done chem since high school either, but I think that H[sub]2[/sub]SO[sub]4[/sub] without water is sulfur dioxide, which is a gas. Sure, it won’t corrode a metal container, but it’s actually easier to work with if you add some water.
It’s true that sulfur trioxide reacts with water to make H[sub]2[/sub]SO[sub]4[/sub], but that doesn’t mean that H[sub]2[/sub]SO[sub]4[/sub] can’t exist without water. If you react just the right amount of water with SO[sub]3[/sub], you get anhydrous (waterless) H[sub]2[/sub]SO[sub]4[/sub] (which won’t attack steel). Then if you add more water you get dilute H[sub]2[/sub]SO[sub]4[/sub], which will attack most metals. H[sub]2[/sub]SO[sub]4[/sub] with or without water is commonly called “sulfuric acid.”
<<I got to wondering about that after finding out how to make the stuff much stronger than what goes into car batteries.>>
Which container did you use to make the stuff stronger? Or did you read about it somewhere and they forgot to mention it?
In order to make it stronger, I read where you take a glass bowl, fill it with the acid from an old car battery and heat it until it steams. (Outside, of course.) As excess water evaporates off, the acid becomes stronger. I did not know that you could virtually render it harmless by removing too much water. I’ll have to get one of those glass acid gauges to determine when it is at it’s most potent. I assumed that it did not eat through car batteries or those plastic shipping bags because it had been diluted heavily.
Apart from playing with fire here you are playing with fire here if you try to concentrate sulphuric acid - there is no sane reason to do this .
Boiling acid is only useful in horror films. Car battery acid is fairly strong as it is and, IIRC, water is driven off during charging and through evaporation from the heat in the car. If the level of acid in the battery is too low, you need to top it up with distilled water.
If you want to concentrate it, don’t - just buy some concentrated acid it’s far easier. There is a danger that it will boil and spit if you try to concentrate it with the risk of severe damage to yourself or your possessions.
Yiu will not make it harmless by evaporating all the water. this cannot be done without industrial equipment.
So be careful and good luck dissolving that body.
PS never add water to concentrated acid it may boil and spit back at you - add the acid to the water.
Bob, I have to disagree. Even pure, anhydrous sulfuric acid is corrosive. The sulfate ion is so repulsive to protons that they come off even out of water solution. Also, pure sulfuric acid is so hygroscopic that unless you’re working in an absolutely dry environment, it immediately becomes concentrated sulfuric acid.
(FTR: The working concentration of concentrated sulfuric acid is 98-99%)
IOW–even if anhydrous sulfuric acid is not corrosive, that’s like saying that seaborgium has such-and-such molecular weight: you’ll never see enough of it to say with any certainty.
