quirkzunc
Harmless
Posts: 4
Registered: 20-7-2008
Member Is Offline
Mood: No Mood
|
|
Test for Bromine vapour.
I am looking for a simple test for the presence of bromine vapor in the steam evolved from a boiling solution. I am thinking along the lines of a
material that I can soak into some filter paper and get a color change in when its placed above the steam.
|
|
|
Picric-A
National Hazard
Posts: 796
Registered: 1-5-2008
Location: England
Member Is Offline
Mood: Fuming
|
|
Well if you use normal PH paper bromine vapour should bleach it white...
what are you doing that evolves bromine and steam?
|
|
|
quirkzunc
Harmless
Posts: 4
Registered: 20-7-2008
Member Is Offline
Mood: No Mood
|
|
Bromine test
A hydrolysis reaction (using sodium bromate) is performed on a platinum chloride solution that is contaminated with other platinum group metal
chlorides(Hydrolysis being necessary to oxidize the contaminants and cause their hydroxides to be precipitated when the pH is raised to 7.5). After
the hydroxides are removed it is necessary to drive away the bromine before the next step in the process by boiling the solution with Hydrochloric
acid. This is why there is bromine in the steam (I forgot to mention that there would be HCl in there as well.
|
|
|
kaviaari
Hazard to Self
Posts: 80
Registered: 21-12-2005
Location: Finland
Member Is Offline
Mood: Going green
|
|
Soak a piece of paper in aq. solution of iodide ions. Potassium iodide works fine. When in contact with bromine the ions get oxidized to iodine. The
paper turns from white to blueish brown.
Br2 + 2I- --> 2Br- + I2
[Edited on 21-9-2008 by kaviaari]
|
|
|
Klute
International Hazard
Posts: 1378
Registered: 18-10-2006
Location: France
Member Is Offline
Mood: No Mood
|
|
You could directly use commercial iodide-starch paper.
Even better, just trap the effluent with a wash bottle full of NaOH solution, it will capture the bromine (forming OBr-) and HCl.
\"You can battle with a demon, you can embrace a demon; what the hell can you do with a fucking spiritual computer?\"
-Alice Parr
|
|
|
unionised
International Hazard
Posts: 5126
Registered: 1-11-2003
Location: UK
Member Is Offline
Mood: No Mood
|
|
IIRC the reaction of fluorescein with bromine to give eosin is pretty specific and reasonably sensitive. It changes from yellow to pink.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
