Sciencemadness Discussion Board

can anyone describe the smell of hbr or hydrobromic acid?

Leafs - 5-12-2017 at 14:09

Google describes it as acrid, but that is kinda open to interpretation. I was wondering if someone could give a more precise description? Is it supposed to smell rotten? Like a really rotten fart?

DraconicAcid - 5-12-2017 at 14:21

It probably smells very much like hydrochloric acid.

DJF90 - 5-12-2017 at 14:23

I find it smells quite fruity actually, but you'd want to avoid breathing it if possible

mayko - 5-12-2017 at 17:17

Quote: Originally posted by Leafs  
Google describes it as acrid, but that is kinda open to interpretation. I was wondering if someone could give a more precise description?


In my very limited experience, it smells indistinguishable from hydrochloric acid, but...
Quote:

Is it supposed to smell rotten? Like a really rotten fart?


.... this reminds me of this passage from a DIY prep for HI from phosphoric acid and potassium iodide:
Quote:

At 65º an obvious reaction will take place. The clear solution will turn dark brown. This is hydriodic acid being formed. Keep the heat on high, don't let off. The solution will begin to boil at 105ºC and a small amount of milky white distillate will come over into the receiver.
(...) the first distillate and the initial gas contain H2S (the same hydrogen sulfide that I mentioned being deadly poison at the beginning of this long-winded tome). My guess is that since phosphoric acid is often made from the reaction of sulfuric acid on phosphate rock, trace amounts of sulfur remain in the phosphoric acid. HI is a powerful reducing agent (that's why the meth guys need it), so there is a redox between HI and any sulfides.


https://erowid.org/archive/rhodium/chemistry/hydriodic.argox...

I can't vouch for the mechanism given, but it might be a clue. How did you acquire this HBr?

Leafs - 5-12-2017 at 18:01

Quote: Originally posted by mayko  
Quote: Originally posted by Leafs  
Google describes it as acrid, but that is kinda open to interpretation. I was wondering if someone could give a more precise description?


In my very limited experience, it smells indistinguishable from hydrochloric acid, but...
Quote:

Is it supposed to smell rotten? Like a really rotten fart?


.... this reminds me of this passage from a DIY prep for HI from phosphoric acid and potassium iodide:
Quote:

At 65º an obvious reaction will take place. The clear solution will turn dark brown. This is hydriodic acid being formed. Keep the heat on high, don't let off. The solution will begin to boil at 105ºC and a small amount of milky white distillate will come over into the receiver.
(...) the first distillate and the initial gas contain H2S (the same hydrogen sulfide that I mentioned being deadly poison at the beginning of this long-winded tome). My guess is that since phosphoric acid is often made from the reaction of sulfuric acid on phosphate rock, trace amounts of sulfur remain in the phosphoric acid. HI is a powerful reducing agent (that's why the meth guys need it), so there is a redox between HI and any sulfides.


https://erowid.org/archive/rhodium/chemistry/hydriodic.argox...

I can't vouch for the mechanism given, but it might be a clue. How did you acquire this HBr?


sodium bisulfate (monohydrate) intimately mixed with sodium bromide, heated strongly in a flat bottom flask attached to a reflux condenser, passed through copper and a drying tube (magnesium sulfate), then bubbled into H2O with an inverted funnel. it resulted in a cloudy solution with a few small clumpy specks of some sort of particulate. solution smells rotten. H2S is apparently only slightly soluble in water and whatever this was appeared to be very soluble... perhaps it was a mixture of gases. I'm going to try again but this time with everything completely anhydrous because I noticed the H2O that initially refluxed from the monohydrate appeared to be largely consumed by the latter stage of the reaction. Oh and bromine oxidation also still occurs with this method.

made another small batch following nurdrage

https://www.youtube.com/watch?v=C3n4Xqfb9qk&spfreload=10

and the resulting product did indeed have a little bit of fruityness too it and doesn't smell rotten.

edit: thinking about it more my choice of drying agent was pretty dumb but it was all I had on hand. I also figured it would be unreactive under these circumstances but now I'm not so sure. so two changes. flask anhydrous and calcium chloride as the drying agent.




[Edited on 6-12-2017 by Leafs]

BromicAcid - 5-12-2017 at 20:19

Smells a bit 'heavier' than HCl, and not trying to be funny with that comment. HCl is biting, HBr has more of a lingering bite, it is similar to the difference in smell between chlorine and bromine. One is tolerable and other much less so.

woelen - 5-12-2017 at 23:57

It smells much like HCl, but besides the acrid/burning sensation, there also is some other smell. HCl is just burning/acrid, HBr has a weak other effect besides the burning/acrid effect. I would describe it as the smell of decomposing leaves, humus-rich soil, or something like that. If it did not have the strong acrid/burning effect, I probably would like the smell of HBr.

[Edited on 6-12-17 by woelen]

Leafs - 6-12-2017 at 21:38

just an update on this reaction.

I now feel I can come to the relatively safe conclusion that this reaction is a no go as the temperature required for these two to react in a solid state kicks off unknown reaction (atleast to me) and results in the production of H2S gas. Initially it formed a heterogeneous mixture with the cloudy (suspected H2S) layer on the bottom. After a short while the mixture became uniform and now appears to be a milky looking solution, same as described in the link that was posted. Anyway I'm done messing with HBr for now, proceed at your own risk.

ave369 - 7-12-2017 at 07:59

I've got a small bottle of HBr in my lab and I've just smelled it. It is indeed more pleasant than HCl, still pretty "chemical" but sweeter and sourer.

Melgar - 8-12-2017 at 16:01

HBr forms vapors far less readily than HCl. In my experience, HBr fumes are usually visible, like a cloud, unless they're at a very low concentration. I've always found the smell of HBr to be oddly mild, and not very unpleasant.

[Edited on 12/9/17 by Melgar]