Sciencemadness Discussion Board - Mixing concentrated acid and base

Mixing concentrated acid and base

EliasExperiments - 15-1-2021 at 06:50

In this video you can see what happens, when you mix concentrated acids with sodium hydroxide:

https://youtu.be/FSfWTNPSaW8

Does anybody have an idea, how you can make such a reaction even more violent?

SWIM - 15-1-2021 at 08:46

You could drop the hydroxide solution into a beaker of sulfur trioxide (liquid, not polymerized)
(Actually, that would be serious overkill, dangerous, and a waste of hard to get materials)

But why would you want to do anything like this?

There are better ways to make things go BANG without throwing all that corrosive material around.

Sure, the ingredients theoretically neutralize each other, but it obviously isn't with all that splashing.

You probably end up with at least a few puddles of concentrated hydroxide here and there that need cleaning up before the neighbor's cat walks through them and gets corrosive burns.

Tiny drops of concentrated hydroxide solution on nearby windows?
Un-reacted acid etching your cement or mortar?

Maybe even a lungful of hydroxide droplets if you're really unlucky.

I bet you can have more fun with less hassle with some of the tamer energetic materials.

aromaticfanatic - 15-1-2021 at 10:58

Even more violent? Heat both up. I have had small boiling occur once when neutralizing some waste water. I let the temp get a bit too hot and when I added just a little bit of sulfuric acid drain cleaner (I added a little since I suspected this would happen) it immediately boiled for a split second where I added the acid. This was already in dilute NaOH solution.

You might be able to to get a more violent reaction by using hot and highly concentrated NaOH and adding hot 98% sulfuric acid to it.

An extremely terrible idea to be honest but hey, it's not me who has to clean the mess and potentially get corrosive material everywhere

Fyndium - 15-1-2021 at 11:10

Mix boiling sulfuric acid and boiling sodium hydroxide.

Ironic to say that energetic materials tend to be more controllable than this stuff.

Junk_Enginerd - 15-1-2021 at 15:46

Yeah I can think of a way to one-up all suggestions so far. Heat up sulfuric acid to boiling (250°C ish), and then pour molten sodium hydroxide in there. Just pouring molten sodium hydroxide into water is extremely violent due to the flash boiling that ensues.

Or use sulfur trioxide(or oleum) instead of sulfuric acid.

I don't like being the safety sally, but I think in this case I really need to add some words of warning to just how dangerous/violent this would be. But, yeah. Be careful.

roXefeller - 15-1-2021 at 17:02

How about adding cold NaOH to cold SA. In sufficient quantities then warming to the melting point of NaOH, that way it doesn't fizzle out half-way through the NaOH addition.

Junk_Enginerd - 16-1-2021 at 04:31

Quote: Originally posted by roXefeller

How about adding cold NaOH to cold SA. In sufficient quantities then warming to the melting point of NaOH, that way it doesn't fizzle out half-way through the NaOH addition.

... Now I'm wondering if it's me or you that's brain farting. NaOH melting point is higher than sulfuric acid's boiling point first of all. Also, even if that wasn't true, no way you could actually do it without starting a violent chain reaction long before heating it significantly.

unionised - 16-1-2021 at 05:28

"NaOH melting point is higher than sulfuric acid's boiling point first of all"
Only a bit.
You could add some KOH to drop the MPt. The eutectic melts at 170C

https://pubs.acs.org/doi/abs/10.1021/je60023a009

Fyndium - 16-1-2021 at 06:36

Mere dropping molten NaOH into boiling H2SO4 isn't fair enough. You should eject them somehow together with great velocity, in order to maximize the surface area of contact, before the generated vapor can push them apart and stop the reaction.

Of course, everyone here understands that these concepts, if performed, should be carried with taking every precautionary measure, because the reaction will pretty much be explosive, in the common terms.

EliasExperiments - 16-1-2021 at 09:35

@SWIM Well listing everything that could possibly go wrong is always easy. Also I cleaned everything up thoroughly after I was done, I might be crazy but not entirely idiotic. About the question why I would do such thing: First of all why not? Second it is always about satisfying curiosity. Cause that was the first time I have ever seen such violent and explosive acid and base reaction.

@aromaticfanatic Yeah heating up is of course always an option. Or maybe using even stronger acids an bases might be more interesting

@Fyndium How are energetic materials more controllable? I don't see how an acid or a base like that might blow up accidentally. But for energetic materials that can easily happen

@Junk_Enginerd That is certainly a great suggestion. I was actually thinking of trying that. I'll consider it for a future video!

@roXefeller that is what I did close to the end of the video and it blew up.

@unionised Also great idea, but might also make the reaction less interesting

@Fyndium I don't think my engineering skills are enough for that sadly.

Thanks for all the feedback! :-)

Vomaturge - 16-1-2021 at 13:00

As far as making this reaction more violent, maybe pouring boiling sulfuric acid into powdered calcium or sodium oxide and molten sodium hydroxide? Maybe saturated sodium hydroxide-water solution, covering a glass bottle of anhydrous hydrogen chloride condensed into a liquid at -85C, so there's a BLEVE and violent mixing when the bottle warms up? Both kinda dumb ideas, since they're just adding a lot of new hazards, and may not make the reaction bigger in the end. The limiting factor in all these reactions seems to be how fast they can mix, how much can actually react, before the steam pressure forces the unreacted acid and base out of the container.

I learned something new, I never would have guessed how much of a difference dissolving the hydroxide would make, but I feel like you could've demonstrated that with just a few grams. Doing whole liters just makes it more more messy, more dangerous, and vastly more expensive. I can't imagine what this experiment costed. H2SO4 and H3PO4 can neutralize more than one mol of sodium hydroxide, so the residue is probably acidic enough to etch concrete or kill plants and animals even after rinsing with water.

An "energetic material" reaction that produces a similar visibile cloud, similar mechanical energy (pushing the container into the air, spraying liquid everywhere, etc) and similar sound would be more "controllable" in the sense that you just have a few grams of material reacting completely. You wouldn't have corrosive residue, or even as much heat energy.

I get the appeal of a big, visually impressive reaction, but I feel like you get just as much excitement with an air pump and a throwaway plastic water bottle that ruptures at 8 atmospheres. Or a 4 liter bottle of air and flammable vapor, with a cardboard tube with a few grams of flammable powder on the end and a thin sheet of plastic bag to keep it from falling into the bottle. Or two tin cans, one slightly bigger than the other, with water in the big one and a hole in the top of the small one for a 50 mg flash powder firecracker. Costs practically nothing, and there's no acid mess to clean up.

[Edited on 16-1-2021 by Vomaturge]

EliasExperiments - 17-1-2021 at 04:43

@Vomaturge Calcium oxide is a great idea. Sodium oxide is probably too difficult for me to get and molten sodium hydroxide I have already noted. Messing with liquid HCl is something I wouldn't dare on a skale like that, cause there would be a very real chance of me dying. In a small scale however that could be interesting.

The experiment wasn't that expensive. I guess 50 €/$
at most for everything included. That is really nothing compared to what other people spend on their youtube videos. I have a more expensive video that I am working on right now which should be safer. The thing is if you are making youtube videos your chances of getting people to enjoy your videos are a lot higher, when you do things on a large skale. Just look at all popular youtube channels or television shows that do science stuff. I am not saying it is the only way, but it is certainly helps.

Well yes there are certainly safer things I could have done, but danger is kind of the point when making interesting videos or content. It is the art of handling dangerous things safely that makes people interested I guess. I mean of course people also love seeing if things go wrong spectacularly, but I'll try to avoid that until I have a higher budget. XD

Yes there are certainly cheaper experiments I could have done, but that it also not the point, I just wanted to do something that nobody really has done before. If you have better ideas that actually have not been done on youtube yet I am open for everything.

pneumatician - 17-1-2021 at 16:19

are you on drugs?

converting the backyard in a landfill of corrosive chems is not a good thing, no?

I hope not, but maybe one day you'll be upset.

you can make the same with some grams, use a macro lens.

SWIM - 17-1-2021 at 18:59

Quote: Originally posted by EliasExperiments

@Vomaturge Calcium oxide is a great idea. Sodium oxide is probably too difficult for me to get and molten sodium hydroxide I have already noted. Messing with liquid HCl is something I wouldn't dare on a skale like that, cause there would be a very real chance of me dying. In a small scale however that could be interesting.

The experiment wasn't that expensive. I guess 50 €/$
at most for everything included. That is really nothing compared to what other people spend on their youtube videos. I have a more expensive video that I am working on right now which should be safer. The thing is if you are making youtube videos your chances of getting people to enjoy your videos are a lot higher, when you do things on a large skale. Just look at all popular youtube channels or television shows that do science stuff. I am not saying it is the only way, but it is certainly helps.

Well yes there are certainly safer things I could have done, but danger is kind of the point when making interesting videos or content. It is the art of handling dangerous things safely that makes people interested I guess. I mean of course people also love seeing if things go wrong spectacularly, but I'll try to avoid that until I have a higher budget. XD

Yes there are certainly cheaper experiments I could have done, but that it also not the point, I just wanted to do something that nobody really has done before. If you have better ideas that actually have not been done on youtube yet I am open for everything.

Calcium oxide and hot sulfuric acid were used in WWI as a method of producing sulfur trioxide clouds for smoke screens.
The mixture gets red hot and decomposes some of the acid to make a corrosive cloud.

It would be easy to list the things that could go wrong with this scenario, but I don't want you to think I'm trying to discourage you from trying it out in your backyard on a large scale.

Sodium in chloroform would be about 100 times more interesting to watch.

Vomaturge - 17-1-2021 at 22:23

I was kind of just saying it theoretically, I didn't expect him to want to try that, least of all with the CaO suspended in molten NaOH.

The chloroform-sodium idea sounds interesting, in a well ventilated area on a gram scale or less. That should be enough to observe how it reacts without making a mess.

As far as making a little boom, and a ridiculously big mess, I think a 12gm disposable steel CO2 or (better yet) N2O cartridge (like they use for whipping cream) A powerful cooking hotplate and 1 liter ish tin can full of flaming vegetable oil would do the trick handily. Please, nobody actually try that. I never have and don't plan on it. The acid-base thing is about the most underwhelming "violent reaction" that still has so much potential danger. Yes, the risks can be managed but what's the point of doing it?

@EliasExperiments, I already gave some cheesy "kewlish" ideas that I've proven to work, and put on as much of a show as this acid boil over but with less danger. I can give more ideas of how to make them novel and educational too, if you'd like.

[Edited on 18-1-2021 by Vomaturge]

EliasExperiments - 20-1-2021 at 09:59

@pneumatician I actually never consumed alcohol so far or anything that could be considered a drug. The backyard is already as clean as ever again, after I washed everything thoroughly with water. Yes you can do things differently I get that.

@SWIM Well making SO3 from CaO and H2SO4 sounds really interesting to me actually. I have to try that. I always try those kind of things on a small skale first. Who says that sodium and chloroform actually do react? I couldn't get sodium to react with carbon tetrachloride only potassium. With NaK it really starts to get intersting. Do you have a specific procedure for the reaction of sodium metal and chloroform?

@Vomaturge: For the cartridges I would use thermite lol. I actually wanted to try that with big gas cylinders so you actually see something on video, but I have to find a good location for that first. The point for me is always to make intersting chemistry or science videos that motivate others to go into these disciplines.
If you have more ideas I'll be more than happy to hear them. If I do end up using them in a video I would obviously credit you for them. Like the calcium oxide sulfuric acid idea, I will credit you for it, once I do it. :-)

Vomaturge - 20-1-2021 at 17:41

If, for some reason you do the CO2 cartridge thing, remember that the hot cartridge could fly hundreds of meters at very high speed after it breaks.

H2SO4 and Ca0 don't just create SO3. Mostly, they make calcium sulfate, plus they evaporate and thermally decompose some sulfuric acid creating a huge cloud of toxic vapor that has a little sulfur trioxide, maybe some calcium sulfate, and a lot of normal sulfuric acid vapor. Not something you want to breathe or expose neighbors to.

EliasExperiments - 24-1-2021 at 22:38

I am 100% sure the CO2 cartridge will not fly hundreds of meters and it will also not be hot, cause the CO2 rushing out of the cartridge will cool it very significantly. My guess is that it will fly at most 10 meters, cause the force will spread out very quickly and nothing will direct it in a certain direction like a gun barrel. Also it probably has very poor aerodynamics.

Okay you are probably right that it is very difficult to use the CaO and H2SO4 reaction to make SO3, because the resulting calcium hydroxide and water will ruin it again. But in an uncontrolled fast reaction I can imagine that quite a bit of SO3 is going to be released.
About the dangers I think you are beeing a bit overly dramatic. First of all it depends heavily on the scale, second it depends on the location and third sulfuric acid or sulfur trioxide is not labled toxic to the best of my knowledge. Of course you wouldn't want to breathe it, but it is also very easy to avoid that cause you can actually see the vapors and you have more than enough warning to run away if the vapors sting your nose. I mean of course if I would do that in a small enclosed room and I lock myself in it could be dangerous, but if I am that stupid my life might as well be over already.

Johnny Cappone - 24-1-2021 at 22:59

Quote: Originally posted by EliasExperiments

and third sulfuric acid or sulfur trioxide is not labled toxic to the best of my knowledge.

Yes, sulfur trioxide is toxic.
But that is of no importance, it would kill you for simple dehydration and corrosion of your airways/ lungs before any toxic effect itself could be felt. From your previous posts, it is clear that you are an excited guy who just created a YouTube channel, would like to see it with several subscribers and believes that reactions where some real danger under control is demonstrated on a large scale is the way to go.

I don't think anyone who minimizes the dangers of the H2SO4 mist generated by the heating of the acid or, even worse, the SO3 itself will last a long time in this hobby. Anyway, stay safe.

ChemTalk - 25-1-2021 at 21:44

Quote: Originally posted by pneumatician

converting the backyard in a landfill of corrosive chems is not a good thing, no?

Well OP is using stoichiometric amounts, so technically they should be neutralizing each other.

Vomaturge - 25-1-2021 at 21:58

He was doing equal mols of NaOH with H2SO4, H3PO4. That's a lot of "acid salts" that alter soil pH, corrode concrete, etc.

outer_limits - 26-1-2021 at 03:02

Molten NaCl to boiling H2SO4

pneumatician - 28-1-2021 at 14:48

Quote: Originally posted by EliasExperiments

@pneumatician I actually never consumed alcohol so far or anything that could be considered a drug. The backyard is already as clean as ever again, after I washed everything thoroughly with water. Yes you can do things differently I get that.

ok, say no to idiotic drugs

maybe hot water in lime (calcium oxide) is another flussssssbangwow one?

USE THE BEST GOOGLES AND FACIAL SHIELD YOU CAN FIND!!

pneumatician - 29-1-2021 at 15:11

Quote: Originally posted by ChemTalk

Quote: Originally posted by pneumatician

converting the backyard in a landfill of corrosive chems is not a good thing, no?

Well OP is using stoichiometric amounts, so technically they should be neutralizing each other.

maybe the projections are chems unmixed... ok the pavement is very hard but I do not go here barefoot :-)