Enclosed Electrolysis of Water Question

[ChrisAndre]

Scenario: Let's say we have ONLY 100% water in an enclosed container that cannot be penetrated. If we run current through it, and the water is completely split into hydrogen and oxygen, then will it:
-Recombine to reform the water?
OR
-Stay separated at the extremely high pressure?

And if we ignite the mixture, will it create a higher pressure because of the reaction?

 

[Borek]

What arguments do you have for both scenarios?

 

[Nik_2213]

Remember the energy you've put into the system...

 

[ChrisAndre]

From just basic experience, I think that it will stay separated, because I've never heard of anything forming bonds when under high pressure. But then again, considering that there is only water in a completely enclosed container, there is really no place to go for the gases created to go, and so I assume the atoms are more or less in the same proximity to each other as when the bonds between them existed. I would guess that they might recombine. I don't know how to start eliminating these possibilities.

If I can ignite the mixture, intuitively it would generate lots of heat. I'm guessing that's what the electricity is converted into.

 

[m3lange]

there is a certain ratio of oxygen and hydrogen where there is a possibility it will spontaneously combust. Something called the explosive limit. Try wiki it.

 

[Borek]

From just basic experience, I think that it will stay separated, because I've never heard of anything forming bonds when under high pressure. But then again, considering that there is only water in a completely enclosed container, there is really no place to go for the gases created to go, and so I assume the atoms are more or less in the same proximity to each other as when the bonds between them existed. I would guess that they might recombine. I don't know how to start eliminating these possibilities.

OK. A lot depends on the system temperature, but as long as temperature is not measured in hundreds of deg C, it is too low to overcome activation energy. In effect gases will stay separated. I have no idea what exact temperatures will let them react, these things are probably measured and available as a tables when you know where to look.

If I can ignite the mixture, intuitively it would generate lots of heat. I'm guessing that's what the electricity is converted into.

That's just energy conservation. You put electrical energy into system, converting it into mechanical (pressure) and chemical (presence of hydrogen and oxygen) energies. Recombination of hydrogen and oxygen means conversion of chemical energy into heat.

there is a certain ratio of oxygen and hydrogen where there is a possibility it will spontaneously combust. Something called the explosive limit. Try wiki it.

Explosive limits (upper and lower) have nothing to do with spontaneity. They separate mixtures that can explode from mixtures that can't, but they don't guarantee mixture will explode just because it exists.