78

The odour threshold for HCN is in fact quite a bit lower than the lethal toxicity threshold. Data for hydrogen cyanide can be found in many places, but here and here are a couple of good references. That subset of the human population that can detect bitter almonds do so at a threshold of 0.58 to 5ppm. The lethal exposure dose is upwards of 135ppm. That's a ...


45

Alle Dinge sind Gift, und nichts ist ohne Gift, allein die Dosis macht dass ein Ding kein Gift ist (The dose makes the poison) - Paracelsus Poisons (I'm going to use this as an umbrella term for "toxins" and "venom" as well. Bear in mind though, they are not the same thing) have been known since antiquity. Back in the good old days, you figured out if ...


43

Forget about the apple seeds, they contain about 1 to 4 mg amygdalin per gramm seeds (DOI). Instead, collect apricot seeds during the right season, the amygdalin content varies though the year and can be as high as 5% of the dry weight of the seed (DOI). It is probably advantagenous to break the husk with a nut cracker, a plier, etc. and cut the softer inner ...


37

I will start my answer with a preface that the website linked to in the question is a pseudoscience website (and I am glad that it has vanished from the face of this earth, only accessible via the Wayback Machine). These people use scientific-sounding jargon that sounds impressive to the lay reader, but any actual scientist will know that it is simply ...


31

Recognize that a whiff of most toxins, even in high concentration, will probably not kill you. You need a sufficient concentration in your blood - which means you have to actually get a certain number of HCN molecules to penetrate across the mucosa of the lung and into the blood stream. Typical breathing volume is about 500 mL (tidal volume), about 1/40th of ...


30

Methanol isn't particularly toxic in and of itself, although it's no walk in the park. If methanol flowed through the body without being broken down, it would cause roughly the same kind of harm as ethanol, i.e. intoxication. The real culprit is one of its metabolic products, methanoic acid, also known as formic acid. To understand how formic acid, ...


29

Table salt! What would be worse than putting sodium (it can spontaneously combust if you get it wet) and chlorine (used as a war gas in WWI) all over your food? Then there's water which always contains some $\rm OH^-$ (an active ingredient in Drano) and $\rm H^+$ (that stuff eats through metal, man). Although those aren't elements. And hiding inside every ...


27

Based on what I gathered from this Wikipedia article, Yes. Drinking copious amounts of water can prove fatal. The proper term is "Water intoxication". When you start taking in a lot of water (by "a lot" I mean more water than your body can excrete via sweat or urine), the interstitial fluid that bathe the cells that form your (living) tissue end up getting ...


26

Cyanide is a pretty good ligand for coordination compounds. The electron pair on carbon (which, incidentally, also carries the Lewis structure’s formal charge) is located in the HOMO — much like as in $\ce{CO}$, whose molecular orbitals can be found in this answer by Martin (replace oxygen with nitrogen to arrive at $\ce{CN-}$) — making it a good Lewis base ...


24

It depends on what the poison is. If we take the colloquial use of the word and include toxins and venoms, many are things like proteins that will certainly denature or otherwise degrade, eventually becoming harmless. e.g. tetrodotoxin, ricin, botulinum, etc. I would expect that type of poison to have the shortest shelf-life as they are relatively fragile. ...


23

Answering my own question based on the comments, tert-butyl-hydroperoxide is at least one such chemical. As stated on this MSDS from a government website, it's a 4-4-4, with additional special warning of being a strong oxidizer. The only thing that it does not do that could make the 704 diamond any worse is react strongly with water. It is in fact water ...


21

Do not do it !! ( putting acidic, or rather any juice to copper bottles ) You are in danger of copper poisoning. Generally, by food processing laws, copper is not allowed to be in direct contact with food, as there is danger of copper contamination. Especially acidic liquids, like vinegar or citrus juices, directly slowly dissolve copper in presence of ...


20

Metallic lead is very low risk. Lead compounds are fairly poisonous: they slowly build up in the body and cause many harmful effects. But lead metal is very inert and you would need to do something fairly risky with it to create much likleihood of generating dangerous lead compounds. Don't eat it, for example. Don't put it in contact with food (especially ...


20

Yes. See Jury Rules Against Radio Station After Water-Drinking Contest Kills Calif. Mom The husband of a California woman who died after participating in a radio station's water drinking contest said he hopes a jury's $16.5 million compensation award following a wrongful death lawsuit will send a message to other corporations dealing with the public. .....


20

Of course no. Botulotoxin is probably the strongest known, and still its $\rm LD_{50}$ is counted in nanograms per kilogram, which is pretty manageable. Sure, working with such tiny amounts requires some special measures, but still, it is way greater than one molecule. You can divide it again, and again, and again. So it goes.


18

The enzyme alcohol dehydroganase converts the methanol to formaldehyde in the body. Formaldehyde is then converted to formic acid. Formaldehyde can cause blindness before being converted to formic acid, while formic acid causes acidosis as Williham Totland points out. See Biochemical Aspects of Methanol Poisoning for more information.


17

The halogens, particularly in their diatomic free states and within various oxoacids, are strong oxidizing agents by virtue of their high electronegativities, electron affinities, and reduction potentials. The polarizability of the heavier halogens also makes them almost uniquely versatile as both good leaving groups and strong nucleophiles, depending on ...


17

Mercury is toxic, but you need to carefully define what you mean by toxic or you draw incorrect conclusions Toxic is a broad term. It means a lot of different things. The timescale matters. Some toxic things take years to exhibit their effects; others act instantly. A binary distinction between toxic and not-toxic is pretty meaningless: you need to define ...


16

Hydrogen cyanide $(\ce{HCN})$ is variously described as smelling of bitter almonds, marzipan, ratafia, or peach kernels. While some people can smell $\ce{HCN}$ at very low concentrations, many people cannot perceive the odour at all. The odour threshold is about $1{-}6\ \mathrm{mg/m^3}$ for people who are actually sensitive to the odour of $\ce{HCN}$. ...


16

As you already correctly deduced, the discovery of poisons was in former times quite accidental, but once its potency was discovered, the (mis)use of it was predictable. It must also be said that our ancestors were very careless with poisonous substances. The old houses used wallpapers and paint which were spiked with arsenic, lead and antimony. Copper ...


15

Looking at the Material Safety Data Sheet (MSDS), most of the issues with it seem to stem from the physical consequences of it being in fine dry powder form. This means that if you get it on your skin, it can get into cracks and pores and easily dry out your skin to the point of cracking, and will cause irritation or worse if you get it in your eyes, for ...


15

No, it is not toxic to touch solid lead. Lead poisoning results from ingestion: paints used to contain lead-based materials, and kids would sometimes eat the peeling paint leading to health problems. inhalation: if you were grinding or polishing a block of lead and fine particles were generated, you might inhale them if you weren't using the proper ...


15

Gatterman reports (Org. Synth. 1927, 7, 50, as a footnote) that people who smoke regularly have enhanced sensitivity to the smell of cyanide gas, and he recommend smoking while preparing it! Organic Synthesis Collective Volume 1 1941 314-315 Just opening the NaCN container, most regular (and former regular) smokers can smell the trace amount of HCN formed ...


14

Nitrogen has a boiling point of 77K (-196 °C), CO2 melts at 195K (-78 °C). You don't cool down the ice cream or whatever else you want to eat to those temperatures, that would be very unsafe. Both will evaporate or sublimate quickly when they are in contact with warmer material, so there won't be much left once you eat e.g. the ice cream. Air is composed of ...


13

Diborane. NIOSH gives NFPA 4-4-4-W:


13

Honestly, you probably wouldn't be able to get this done with just a highschool chem lab, at least not to a high purity (whether or not this is needed is debatable; in fact it could be interesting in the story because it would give a clue as to how it was produced, whereas pure cyanide wouldn't really tell the detective much). Having said that, apples don't ...


11

The Wikipedia article you quoted clearly says: The low toxicity is relevant to the widespread use of tin in dinnerware and canned food. Moreover, tin cookware, which used to be very common in earlier centuries, is still sold for outdoor cooking purposes. It is thus without a doubt deemed safe to use under current health regulations. As a side note, the ...


11

The toxicity of formaldehyde is dose-dependent. The famous saying "the dose makes the poison" is one of the rules of thumb about toxicology. Your body can effectively detoxify small amounts of formaldehyde in a given amount of time, however if you are exposed to concentrations that result in you ingesting/inhaling more than what your body can metabolize, ...


10

It's essentially chalk. I'm not aware of any longitudinal studies of gymnasts' long term exposure to powdered calcium carbonate, but my sense is that the worst that can happen is your skin can get dry and irritated. If you have a part time job as a hand model, you will want to be especially careful to avoid skin contact. If you're in a lab, of course, it ...


10

I'm less familiar with safety regulations elsewhere in the world, but in the US, "chemical manufacturers" (which includes soap, sugar, salt, and just about everything else you can imagine) have to produce Materials Safety Data Sheets (MSDS) and make them publicly available. Out of curiosity, I did some digging for soaps. Proctor and Gamble is a huge ...


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