Chemically dissolve aluminum?

  • Thread starter bikeguy
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I've dissolved aluminum foil in methanol when I used a sonicator.
Can you detail? I didn't know it.
 

chemisttree

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I was trying to ultrasonically clean a bit of aluminum foil and I chose methanol as a solvent. After a couple of minutes in the sonicator... swiss cheese. It made aluminum methoxide I believe. Kind of dangerous and I didn't repeat it.
 

morrobay

Gold Member
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Sodium hydroxide does dissolve aluminum.
We used to make "gas" baloons by adding aluminum foil to a lye solution.
2H2O + 2NaOH +2Al ---> 2NaAlO2 + 3H2
Clarification :
2Al + 6NaOH ---> 2Na3AlO3 + 3H2
This is a more accurate since the water in the first reaction just moves the ions around during the reaction and is not involved in hydrogen being reduced to hydrogen gas
 
1,899
45
Clarification :
2Al + 6NaOH ---> 2Na3AlO3 + 3H2
This is a more accurate since the water in the first reaction just moves the ions around during the reaction and is not involved in hydrogen being reduced to hydrogen gas
Are you sure Na3AlO3 really exists? Anyway, I don't see any problem in the previous reaction you wrote:

2Al + 2NaOH + 2H2O ---> 2NaAlO2 + 3H2
 

Borek

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Compounds like aluminates are notoriously difficult to describe, as their composition - in terms of number of water molecules and OH- attached to the cation - is a matter of multistep equilibrium. Hence you will find different formulas in different sources.
 
1,899
45
Compounds like aluminates are notoriously difficult to describe, as their composition - in terms of number of water molecules and OH- attached to the cation - is a matter of multistep equilibrium. Hence you will find different formulas in different sources.
Yes, this is true, but that one I've never seen it before.
 

morrobay

Gold Member
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Are you sure Na3AlO3 really exists? Anyway, I don't see any problem in the previous reaction you wrote:

2Al + 2NaOH + 2H2O ---> 2NaAlO2 + 3H2
+ ---
Hello, no im not sure it exists ,but i dont have a problem with 3Na and AlO3
in solution.
The problem with the previous reaction i was having is that it implies that the hydrogens
in the two waters are reduced/released in the product as hydrogen gas.
And I could not see any mechanism for that in the reaction with NaOH and Al.
If you can describe that mechanism I would appreciate it
(please place the pos & negs over the ions)
 
1,899
45
+ ---
Hello, no im not sure it exists ,but i dont have a problem with 3Na and AlO3
in solution.
The problem with the previous reaction i was having is that it implies that the hydrogens
in the two waters are reduced/released in the product as hydrogen gas.
And I could not see any mechanism for that in the reaction with NaOH and Al.
If you can describe that mechanism I would appreciate it
(please place the pos & negs over the ions)
Al reacts with water when the oxide layer is removed:

2Al + 3H2O --> Al2O3 + 3H2

NaOH dissolves the oxide layer.
 

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