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View Full Version : Calling chemists: potassium as a weapon?



Albedo
03-10-2014, 04:41 PM
My secondary-antagonist-who-desperately-wants-to-be-MC is trapped in a laboratory by the really bad guys, on top of a bench, with nothing but a rack of common lab chemicals to defend herself. She needs to create either a sufficient distraction or sufficient havoc to escape.

She's already thrown nitric acid in the face of one pursuer: this hasn't slowed the others down. I should mention they are afflicted with an alien virus that gives them powers of regeneration, so stopping them requires substantial damage.

I have her spy a vial of potassium metal in oil. She thinks quickly, lets a flood of water from a tap into the floor, then rolls the vial off the bench, jumping away.

1. Will the potassium react with the water sufficiently violently to damage her other pursuer? They basically need a jaw blown off to slow them down. The amount of potassium can be as large as needed. This takes place in a world equivalent to the late Victorian era, so there's no such thing as lab OH&S. :D

2. What alternate distractions could SAWDWTBMC create, purely with what chemicals are in reach? Massive amounts of chlorine gas, or something like that? Like I said, OH&S is not an issue.

Thanks, fellow FBI-watchlisters!

Torgo
03-10-2014, 06:03 PM
My secondary-antagonist-who-desperately-wants-to-be-MC is trapped in a laboratory by the really bad guys, on top of a bench, with nothing but a rack of common lab chemicals to defend herself. She needs to create either a sufficient distraction or sufficient havoc to escape.

She's already thrown nitric acid in the face of one pursuer: this hasn't slowed the others down. I should mention they are afflicted with an alien virus that gives them powers of regeneration, so stopping them requires substantial damage.

I have her spy a vial of potassium metal in oil. She thinks quickly, lets a flood of water from a tap into the floor, then rolls the vial off the bench, jumping away.

1. Will the potassium react with the water sufficiently violently to damage her other pursuer? They basically need a jaw blown off to slow them down. The amount of potassium can be as large as needed. This takes place in a world equivalent to the late Victorian era, so there's no such thing as lab OH&S. :D

2. What alternate distractions could SAWDWTBMC create, purely with what chemicals are in reach? Massive amounts of chlorine gas, or something like that? Like I said, OH&S is not an issue.

Thanks, fellow FBI-watchlisters!

As usual Mythbusters have done the work - they dropped 2.5kg of potassium metal into a bathtub, and they managed to crack the bathtub, but it wasn't the hand-grenade-like blast they were after.

Sodium and potassium don't seem to give enough of a bang; more reactive alkali metals like caesium seem to react too quickly to create enough pressure (hydrogen buildup seems to be the thing.) You might need to think of something else.

King Neptune
03-10-2014, 06:05 PM
My secondary-antagonist-who-desperately-wants-to-be-MC is trapped in a laboratory by the really bad guys, on top of a bench, with nothing but a rack of common lab chemicals to defend herself. She needs to create either a sufficient distraction or sufficient havoc to escape.

She's already thrown nitric acid in the face of one pursuer: this hasn't slowed the others down. I should mention they are afflicted with an alien virus that gives them powers of regeneration, so stopping them requires substantial damage.

I have her spy a vial of potassium metal in oil. She thinks quickly, lets a flood of water from a tap into the floor, then rolls the vial off the bench, jumping away.

1. Will the potassium react with the water sufficiently violently to damage her other pursuer? They basically need a jaw blown off to slow them down. The amount of potassium can be as large as needed. This takes place in a world equivalent to the late Victorian era, so there's no such thing as lab OH&S. :D

Yes, a large chunk of K will make a rather substantial explosion. Look on youtube for videos of a few grams. I would suggest that a pound of K would be adequate for her to jump out a window while the others are taking cover.
http://www.instructables.com/id/Sodium-and-Potassium-In-Water/


2. What alternate distractions could SAWDWTBMC create, purely with what chemicals are in reach? Massive amounts of chlorine gas, or something like that? Like I said, OH&S is not an issue.


Sodium also explodes nicely. That chlorine gas idea might work, but it would take a lot to do much. Chlorine just sits there and chokes people, but it might hide her departure.

bookworm92
03-10-2014, 06:34 PM
Back in school,my Chem teacher showed us this demo- potassium with cold water.The reaction was slightly violent, but no explosion. If you use a lot of potassium, it may work.

Also you can try having her dropping it in acid. (This is very dangerous, so you SAWDWTBMC should be careful)

Telergic
03-10-2014, 07:00 PM
IMO no common chemical or metal will do anything violent enough in a physical reaction to seriously affect regenerating bad guys unless the lab is actually working on explosives. If the lab is not working with some really dangerous material in large quantity -- unlikely -- most of the simple things that could be done would be no more than annoyances. If a momentary distraction is all that's needed, then there are many possibilities, but if you really need to defeat an enemy, that's going to be hard. As for the particular example of potassium, is it really plausible to have a kilo of potassium metal sitting around in a laboratory? Seems extremely improbable.

I think you might previously establish some special weakness, e.g. to chlorine gas, which is very easy to synthesize, but which I think couldn't reasonably be generated in sufficient quantity to disable ordinary people running for a couple of seconds through a big lab room. Depending on the chemistry being done, it's plausible that all kinds of extremely deadly poisons be available right at hand, for example cyanide, but then you have to get the bad guys to ingest it somehow.

There are a few poisons that are so deadly you just need skin contact with milligrams worth of the stuff to kill, but these are not reasonably going to be sitting around in a lab waiting to kill the chemists unless it's previously been established that's what the lab is working with.

veinglory
03-10-2014, 07:49 PM
You have more luck finding a way to inject them with a potassium solution

wendymarlowe
03-10-2014, 08:21 PM
I know you said Victorian era, but I rather like the idea of setting a large amount of sodium/potassium around and then turning on the sprinkler system :-P

Kregger
03-10-2014, 10:45 PM
You're using the wrong solvent. Water's good, but doesn't explode like anything based on petroleum. Even in Victorian times they understood petroleum products. I can't speak for what was available, but ether in any form is volatile and explosive. It works better as an explosive in vapor form. The trick is to heat it gently to vaporize it without flames. I don't know any lab worth its weight in salt that wouldn't have petrolem solvents. A few other chemicals to consider are Carbon Tetra Chloride and MEK.

Also, if you have enough time, nitric acid can be used to make (organic chem was 30+ years ago) nitro cellulose(?) which flames like magician's powder with a spark. Big flame plus + petroleum distillate + a lot of air = well, you're the writer. How big and how bad is up to you.

Kregger

jeffo
03-11-2014, 12:25 AM
Does it have to be so accurate? I mean, as a reader, I'd accept that the MC threw the entire rack, or knocked it over, and the combination created an acidic smokescreen or an explosion enough for a distraction/escape. Maybe that's just me. :)

veinglory
03-11-2014, 12:27 AM
It is something covered in high school chemistry--so it could annoy a few people if it is way unrealistic IMHO. I think that if you can be accurate, why not.

jaksen
03-11-2014, 12:38 AM
My chem teacher did this when I was a junior in high school. She had long dark hair which she was always swinging around. (Seriously, she could have sat on her hair.)

Anyhow, she meant to drop a tiny piece of potassium into a beaker, but instead dropped the whole block - about the size of a small plum. Fire. Small explosion. Hair on fire.

We all ran out and pulled the fire alarms. It was an exciting day.

When she came back, she'd trimmed her hair as the ends were burned.

So you should get a small explosion and a fire. The fire would definitely push back the attackers for a few seconds. Or the sheer surprise of the explosion/fire would do the same.

She could also open the gas jets in the lab, and light a match - at the jets, that is. If they are pointing in the right direction there will be a flame.

Cath
03-11-2014, 01:10 AM
Does it have to be so accurate? I mean, as a reader, I'd accept that the MC threw the entire rack, or knocked it over, and the combination created an acidic smokescreen or an explosion enough for a distraction/escape. Maybe that's just me. :)

The purpose of this part of the forum is to allow writers to research and use information that makes the story as accurate and believable as possible. While a writer may well decide that the level of detail provided in the answers here isn't needed for their story, we still aim to give as much detailed information appropriate to the question as possible and leave the ultimate decision up to the the writer since only they know best what the story needs.

NeuroGlide
03-11-2014, 03:13 AM
It's less important the amount of sodium or potassium than the form. You'll only get chemical reactions on the metal's surface. The more surface, the more reaction. One pound of filings will give you a far bigger reaction than a one pound block.

waylander
03-11-2014, 02:15 PM
You're using the wrong solvent. Water's good, but doesn't explode like anything based on petroleum. Even in Victorian times they understood petroleum products. I can't speak for what was available, but ether in any form is volatile and explosive. It works better as an explosive in vapor form. The trick is to heat it gently to vaporize it without flames. I don't know any lab worth its weight in salt that wouldn't have petrolem solvents. A few other chemicals to consider are Carbon Tetra Chloride and MEK.


This strikes me as more along the correct lines. An ether flash is nasty but very quickly burns out. You need less volatile solvents to create more of a barrier so roll a few Winchesters of 80-100 Pet ether or Toluene after the potassium.
Wouldn't bother with CCl4 unless you plan on giving them cancer in 40 years time.

Cathy C
03-11-2014, 03:46 PM
I'm sort of surprised nobody has mentioned this, but maybe when people think "Victorian", they sort of forget that the same time period, in a different part of the world, was called "the Old West."

What about plain old nitroglycerin? It was marketed (yes, to labs and doctors) as Trinitrin (http://en.wikipedia.org/wiki/Glyceryl_trinitrate_(pharmacology)), and was widely available in Europe. It was considered dangerous (no duh!) but doctors still played around with the stuff, trying to discover if it had any medicinal value. It did, FWIW. It was, and still is, terrific for stopping heart attacks, but it took some time to work out the dosage.

Anyway, a bottle of that on the shelf, which probably wouldn't even be under lock and key, would do everything you need. Just call it by the market name and let readers scramble to figure it out. :D

Albedo
03-11-2014, 03:55 PM
Thanks! So many great answers in this thread. I think I'll have to go with using it as a distraction, not to actually maim. The character is thinking on her feet and doesn't really have time to synthesise anything special. She's not an expert chemist, either, so might not automatically think of using toluene. I think the bang should be sufficient to give her time to run. Also, shrapnel from the heavy glass container can do wonders. There can still be shrapnel, right?

Cathy C
03-11-2014, 05:52 PM
For nitro, it wouldn't take an expert chemist. It was all over the news, which is why doctors used the Trinitrin name on bottles--because people recognized it by the smell and name when they walked in the office. It was quite common. The average person on the street would know it would blow up if jiggled. If there was just a tiny amount in the bottom of a bottle, it would do the job by throwing it. :)

asroc
03-11-2014, 06:47 PM
The average person on the street may think it blows up when jiggled, but medical nitroglycerin doesn't explode. It is too diluted and stabilized to be any danger. You can throw it around all you want and nothing's going to happen. (The bottles in our medic bag certainly get shaken up enough.)

Cathy C
03-11-2014, 07:43 PM
But in the 1870s? Was it still shipped stable for a Victorian era setting?

asroc
03-11-2014, 08:37 PM
Missed the 1870s bit, however according to my googling Alfred Nobel worked out how to stabilize nitroglycerin in the 1860s, making dynamite, and before that the sale of liquid nitroglycerin was widely banned because of so many accidents. At that point the medical uses of nitroglycerin were only in the very beginning stages of being discovered, and yes, the nitroglycerin Murrell used to treat angina pectoris was already heavily diluted.

Bolero
03-11-2014, 11:29 PM
Modern labs of course have all sorts of hazard symbols - which are very helpful to anyone wanting a bottle of explosives.
These didn't exist in the Victorian era - anyone know what the level of labelling was back then?

Further thought - tipping acid across the floor as well - might hurt their feet long enough to get out the window.

Could also just go for chemical soup so to speak, random throwing of glass bottles at them and the floor. If you mix alkali and acid then there will be heat, fizzing and gases (depending on the starting materials). Organic liquids catch fire in the mix. My mind has faded a bit, but if you google modern safety regs on what to store separately, then that will tell you what to throw in the mix. Chemical stores have separate areas for acids, alkalis and I think organic solvents are split out as well.

Mark G
03-19-2014, 02:56 AM
A great distraction might be something like this... http://en.wikipedia.org/wiki/Thermite

Worked great in my high school chem lab.

King Neptune
03-19-2014, 04:05 AM
A great distraction might be something like this... http://en.wikipedia.org/wiki/Thermite

Worked great in my high school chem lab.

Yes, thermite can create major distractions. Did you build a hatchway to the room below?

And thermite was discovered in the 1890's, so it fits the period involved.