Which of these would you consider the most hazardous?

[JaidynM]

Out of 2M hydrochloric acid, 0.1M silver nitrate, 0.5M barium chloride and solid barium sulfate, which would you think is the most hazardous? I've looked through the MSDS's of all four and I'm leaning towards the HCl, not only because of it's corrosiveness but also its incompatibility with pretty much everything and the fact that its highly concentrated. The barium chloride however, can apparently cause organ failure in high doses as well as some other nasty stuff like diarrhoea and convulsions. What do you think?

[keltingmeith]

... Why do you need to know the most hazardous...?

HCl. 2M isn't particularly strong, but AgNO3 was already pretty docile, and with 0.1M for one experiment nothing's going to happen. As for BaSO4, it might do stuff like that at HIGH concentrations, but what you've got is <1M, that ain't going to do shit unless you eat it. HCl might not be as nasty (at least to you, I wouldn't mess with an acid...), but you're more likely to accidentally spill something on your arms than eat one of the chemicals you're dealing with, and that HCl will eventually eat through your labcoat and go to the skin.

[JaidynM]

We have to fill out a risk assessment form for a prac.

Thanks heaps! Just out of curiosity, what would be considered to be concentrated? Something >10M?

[keltingmeith]

We have to fill out a risk assessment form for a prac.

Thanks heaps! Just out of curiosity, what would be considered to be concentrated? Something >10M?

I got that much, it still seems odd to have to rank things in terms of dangerous - if it's in a lab, you should assume it's dangerous, and take care. It doesn't matter if there's something more dangerous than it or not. Hell, in a uni lab report, I'd just label the HCl and BaCl as mid-risk, and the other two as low.

To memory, highly concentrated sulfuric acid is ~20M?

[JaidynM]

It is a bit odd but it's one of the questions on the form; it does however ask which is the most hazardous as opposed to rank them in order of dangerousness.

While I've got you here, it asks you to write a 'conclusion of risks', would simply saying avoid direct contact/ingestion/inhalation of all materials suffice? I'd probably also add that at such low concentrations they are unlikely to cause significant damage to anything unless a large amount is ingested or inhaled.

[keltingmeith]

I'd probably also add that at such low concentrations they are unlikely to cause significant damage to anything unless a large amount is ingested or inhaled.

NEVER suggest that anything in the lab isn't dangerous. The beaker you're using may have housed hydroflouric acid earlier, and there may still be trace amounts. If you then ingest that, and just a drop or two of hydroflouric acid gets into you, you are dead. (you don't need to worry about this in a high school setting, you will never work with anything this dangerous unless your teacher gives you plenty of warning) (also HF would just eat through the beaker, but, I digress)

Just mention what to avoid/how to fix it if something goes wrong. You do not need to identify if something isn't dangerous, only if it is particularly. (for example, magnesium burns very brightly - in a risk assessment, I would always identify to not ingest, but I'd make a particular note not to look at it directly if setting it on fire)

[JaidynM]

Good point! Thanks heaps, I appreciate the help!

[Kel9901]

Out of 2M hydrochloric acid, 0.1M silver nitrate, 0.5M barium chloride and solid barium sulfate, which would you think is the most hazardous? I've looked through the MSDS's of all four and I'm leaning towards the HCl, not only because of it's corrosiveness but also its incompatibility with pretty much everything and the fact that its highly concentrated. The barium chloride however, can apparently cause organ failure in high doses as well as some other nasty stuff like diarrhoea and convulsions. What do you think?

Barium sulfate is last- it's insoluble in water so the toxic barium isn't really gonna get into you
Silver nitrate 2nd-last- low concentration, not THAT dangerous
I'd say that 2M hydrochloric acid and 0.5M barium chloride are about equal, but the latter is probably more dangerous if ingested (and the former if externally contacted)