86 votes
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How do people know HCN smells like almonds?

The odour threshold for hydrogen cyanide $(\ce{HCN})$ is in fact quite a bit lower than the lethal toxicity threshold. Data for $\ce{HCN}$ can be found in many places, but here and here are a couple ...
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45 votes
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How do I extract cyanide from apple seeds?

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 ...
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45 votes
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How are poisons discovered? Does someone have to die/be poisoned from it first?

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 "...
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38 votes
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Does benzene's resonance structure allow it to enter DNA?

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 ...
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35 votes

How do people know HCN smells like almonds?

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 ...
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34 votes

Are there any good examples of commonly ingested molecules that contain particular toxic individual elements?

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 ...
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32 votes
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Why is methanol toxic?

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 ...
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29 votes
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Can drinking a lot of water be fatal?

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 ...
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29 votes
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Is Fluorine more toxic than Chlorine?

Fluorine is much more reactive than chlorine and would certainly cause more damage to living tissues. You can even check out https://www.youtube.com/watch?v=vtWp45Eewtw for some fun demonstrations of ...
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  • 1,472
28 votes
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What chemical properties of ethanol make it usable for drinks as compared to that of methanol?

The problem arises from the metabolized products of methanol. Methanol oxidizes in the liver by an enzyme called alcohol dehydrogenase to formaldehyde which is further metabolized to formic acid by ...
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27 votes
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Why is the cyanide ion toxic?

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 ...
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26 votes
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Is poison still poisonous after its 'expiration date'?

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 ...
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23 votes

How toxic chemically is plutonium (Pu), neglecting the radioactive damage?

The toxicity is primarily due to radioactivity and to absorption by the body, where that radioactivity can act internally. There is, "significant deposition of plutonium in the liver and in the &...
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21 votes

Can drinking a lot of water be fatal?

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 ...
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21 votes

Any substance too poisonous to measure an LD50?

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 ...
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21 votes

Chilling water in copper vessel

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 ...
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21 votes

Why is potassium ferrocyanide considered safe for consumption, when it is just one reaction away from the highly toxic potassium cyanide?

Under biological conditions it is almost impossible to release HCN Free cyanide can be released from potassium ferrocyanide by heating or by strongly acidic conditions (and some heat). Neither of ...
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20 votes
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Is there any substance that's a 4-4-4 on the NFPA diamond?

Diborane. NIOSH gives NFPA 4-4-4-W:
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20 votes
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Toxicity of metallic lead (Pb)

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 ...
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19 votes

Why is methanol toxic?

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 ...
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  • 39k
19 votes

How toxic chemically is plutonium (Pu), neglecting the radioactive damage?

Actual toxicity other than radioactivity is not, as far as I know, very well studied. Quite simply, most of the danger is the radioactivity in general, as well as the toxicity of decay products (...
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18 votes

How do people know HCN smells like almonds?

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 ...
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  • 6,488
18 votes
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Mercury metal: Not toxic?

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 ...
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  • 32.6k
17 votes

Toxicity of a sheet of lead?

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....
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16 votes

How are poisons discovered? Does someone have to die/be poisoned from it first?

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 ...
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16 votes
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Can osmium react with oxygen at room temperature?

From Encylopedia Britannica: Of the platinum metals, osmium is the most rapidly attacked by air. The powdered metal, even at room temperature, exudes the characteristic odour of the poisonous, ...
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14 votes

How do I extract cyanide from apple seeds?

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 ...
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  • 804
13 votes
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How does one tell (or conclude) if a substance is carcinogenic?

How do we tell or suspect one compound to be carcinogenic? As written in the comments to the question, this the result of large studies on the human population, correlating blood or urine levels of ...
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  • 6,758
13 votes

Is Fluorine more toxic than Chlorine?

Fluorine is in the first place much more reactive than chlorine. In contrary to chlorine, it would not damage biological tissues. It would destroy them. Pure fluorine could put the body on self-...
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