kevinlimse - 24-10-2004 at 23:25
I dropped Magnesium Ribbon in NaCl solution, the whole ribbon turned grey slowly with effervescence, it could not be displacement, and magnesium does
not react with water, what could be happening?
Was it tap water?
Hermes_Trismegistus - 25-10-2004 at 03:32
If so, it may have simply be oxidation with dissolved gasses catalysed by the presence of salt.
Try the experiment again, but first boil distilled water to remove a sgnificant amount of the gasses.
EDIT: remember the scientific method; Observations--->Testable Hypothesis---->Experiment(results in further observations)
[Edited on 25-10-2004 by Hermes_Trismegistus]
vulture - 25-10-2004 at 08:30
Magnesium reacts very slowly with cold water, but contaminants like NaCl can greatly speed it up.
What you're seeing is simply Mg + H<sub>2</sub>O ---> H<sub>2</sub> + MgO
MgO will then slowly react with water MgO + H<sub>2</sub>O --> Mg(OH)<sub>2</sub>
[Edited on 25-10-2004 by vulture]
mick - 25-10-2004 at 10:58
The chemicals in the water can catalize the reaction. Sodium verses magnesium should win , but magnesium metal verses sodium chloride in water, that
is called a fight.
mick
Edit
Magnesium can precipitatate, sodium does not usually
[Edited on 25-10-2004 by mick]
Pyrovus - 26-10-2004 at 18:18
The NaCl could be catalysing it by something along these lines:
Mg +2NaCl -> 2Na + MgCl2
2Na + 2H2O -> 2NaOH +H2
MgCl2 + 2NaOH -> Mg(OH)2 +2NaCl
[Edited on 27-10-2004 by Pyrovus]
true_alchemy - 16-12-2004 at 17:59
Yes Mg does react with water. It requires a "dangerous when wet" label. I agree with vulture that salts may speed it up. Turnings or chips
react very vigorously with hot water and can get violent. It seems to hesitate at first. This could indeed be due to the need to first form some
Mg(OH)2 to get it going vigorously. It simply forms Mg(OH)2 + H2.
I am always very careful with wet Mg. In my experience it gets hot and evolves H2 until the water is gone. They say if you throw water on burning Mg
it explodes. I've never tried that and don't think I would want to.
[Edited on 17-12-2004 by true_alchemy]
HNO3 - 16-12-2004 at 18:45
I've tried it. If youv'e got a block of burning Mg, Get Out The NaHCO3 OR TOTALLY GET OUT OF THERE!!!!!!!!!
With NaHCO3, I had some go through 3/4" of wood before it went out.
I never had a problem with Mg reacting with any nonacidic soulution. However, I'm using nonchlorinated ground water.
neutrino - 17-12-2004 at 10:14
I don't think that this is a good idea. Remember that Mg burns in dry ice. Room temp CO<sub>2</sub> would likely make it worse
(higher concentration of available oxygen). Baking soda would also release water, which would also react.
HNO3 - 17-12-2004 at 15:26
Maybe that's why it burnied so well.