Keras
National Hazard
Posts: 929
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
Highly concentrated NaOH solution in microwave → sodium fire?
Folks,
I was attempting to microwave-heat a concentrated NaOH solution stored in a small 25 ml TPX beaker when I got a pretty large number of orange sparks
and occasionally transient orange flames, very characteristic of sodium.
It’s like microwave heating was forming small beads of sodium which were set on fire. That’s not a very satisfactory explanation. Does anyone
possibly know what's going on here?
Cf. attached video
Attachment: IMG_0181.m4v (4.6MB)
This file has been downloaded 592 times
[Edited on 11-6-2019 by Keras]
|
|
|
Sulaiman
International Hazard
Posts: 3721
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
conductive loops convertng microwave to heat energy, exciting the sodium ions (!)
I guess a similar result with NaCl ?
I guess not metalic sodium production.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Ubya
International Hazard
Posts: 1247
Registered: 23-11-2017
Location: Rome-Italy
Member Is Offline
Mood: I'm a maddo scientisto!!!
|
|
if this happened after the solution started boiling maybe droplets formed by the boiling absorbed enough microwaves to ionize, the yellow is the
characteristic color of sodium
---------------------------------------------------------------------
feel free to correct my grammar, or any mistakes i make
---------------------------------------------------------------------
|
|
|
RogueRose
International Hazard
Posts: 1595
Registered: 16-6-2014
Member Is Offline
|
|
I get similar results when boiling down KCl solutions, I get small sparks/flames on the surface when it is near peak saturation and boiling.
|
|
|
Keras
National Hazard
Posts: 929
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
I’ll try with NaCl and see if I get the same thing.
Quote: Originally posted by RogueRose  | | I get similar results when boiling down KCl solutions, I get small sparks/flames on the surface when it is near peak saturation and boiling.
|
Are your sparks/flames red, which would indicate K+ ions?
[Edited on 11-6-2019 by Keras]
|
|
|
Keras
National Hazard
Posts: 929
Registered: 20-8-2018
Location: (48, 2)
Member Is Offline
|
|
I confirm a saturated NaCl solution produces the same yellow sparks (no flame, though)
I think this happens, as someone suggested, when small droplets that adhere on the walls of the beaker boil and evaporate, and the salt crystallises
out. It may happen when crystals form, because I also see sparks under water.
I tried with dry sodium chloride, got nothing. Stopped after a short while, I didn’t want to fry the magnetron.
[Edited on 11-6-2019 by Keras]
|
|
|
RogueRose
International Hazard
Posts: 1595
Registered: 16-6-2014
Member Is Offline
|
|
| Quote: Originally posted by Keras | I’ll try with NaCl and see if I get the same thing.
| Quote: Originally posted by RogueRose | | I get similar results when boiling down KCl solutions, I get small sparks/flames on the surface when it is near peak saturation and boiling.
|
Are your sparks/flames red, which would indicate K+ ions?
[Edited on 11-6-2019 by Keras] |
The are small enough to be difficult to tell what color they are, they look more like sparks and I would say they are more yellow than purple/red. I
don't know how pure the KCl was, it might have been 95/5% KCl/NaCl.
|
|
|
happyfooddance
National Hazard
Posts: 530
Registered: 9-11-2017
Location: Los Angeles, Ca.
Member Is Offline
Mood: No Mood
|
|
This happens in general with ionic solutions, especially concentrated ones. It's the reason I don't heat salt solutions in the microwave (ruined too
many microwaves, think I'm on number 3 or 4).
I would also be very careful because the container can get extremely hot right at the surface, forming a ring. Plastic may melt and the contents will
start to pour out.
I once was dissolving a few hundred grams of KNO3 in water in a mason jar in the microwave, which used to be my preferred method for this scale, when
the sparks got out of hand. I turned it off, but the jar split perfectly in half about the liquid interface. So I don't do that anymore...
|
|
|
mayko
International Hazard
Posts: 1218
Registered: 17-1-2013
Location: Carrboro, NC
Member Is Offline
Mood: anomalous (Euclid class)
|
|
May be related?
https://www.sciencemadness.org/whisper/viewthread.php?tid=63...
al-khemie is not a terrorist organization
"Chemicals, chemicals... I need chemicals!" - George Hayduke
"Wubbalubba dub-dub!" - Rick Sanchez
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
