86
votes
Accepted
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 ...
- 11.9k
45
votes
Accepted
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 "...
- 18.5k
38
votes
Accepted
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 ...
- 70.9k
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 ...
- 786
29
votes
Accepted
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 ...
- 18.5k
29
votes
Accepted
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 ...
- 1,556
28
votes
Accepted
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 ...
- 24.9k
27
votes
Accepted
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 ...
- 67k
26
votes
Accepted
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 ...
- 12.8k
24
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 &...
- 29.7k
22
votes
Accepted
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 ...
- 35.1k
22
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 ...
- 37.9k
21
votes
Accepted
Is there any substance that's a 4-4-4 on the NFPA diamond?
Diborane. NIOSH gives NFPA 4-4-4-W:
- 3,290
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 ...
- 40.1k
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 ...
- 30.9k
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 ...
- 35.1k
19
votes
Accepted
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 ...
- 35.1k
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 (...
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 ...
- 6,586
17
votes
Accepted
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, ...
- 21.1k
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 ...
- 341
13
votes
Accepted
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 ...
- 6,851
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-...
- 37.9k
12
votes
What makes formaldehyde 'safe' or 'dangerous'?
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 ...
- 138
11
votes
How are poisons discovered? Does someone have to die/be poisoned from it first?
Sometimes poisons are discovered by chance.
At least that is what happened to me.
We were researching on products made with malonodinitrile and enones.
Since I was interested in the mechanism, I used ...
- 4,292
11
votes
Can osmium react with oxygen at room temperature?
As the others already stated, handling pure Osmium is too dangerous at home, but there are shops that offer small samples of elements sealed in acrylic glass, which is supposed to be safe. Maybe this ...
- 211
10
votes
Accepted
Why is carbon monoxide not a greenhouse gas?
$\ce{CO}$ is not considered a primary (or significant) greenhouse gas due to the weak (but non-zero) absorption of energy in the infrared. However, it does increase global warming by reacting with ...
- 10.6k
10
votes
What chemical properties of ethanol make it usable for drinks as compared to that of methanol?
Nilay's answer, as well as the comments, do a great job of explaining why methanol is toxic (and ethanol is comparatively less toxic). I'll take a different approach here: I'll explain why ethanol is ...
- 6,208
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