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I was researching how to make pure sodium from salt because I think it would be interesting to do. In all of the articles I read that talked about using $\ce{NaCl}$ they said to melt it and then use electrolysis. Would dissolving the $\ce{NaCl}$ in water then using electrolysis work? Electrolysis of $\ce{NaCl}$ dissolved in water produces $\ce{H}$ gas at one electrode and $\ce{Cl}$ gas at the other, which would leave $\ce{O}$ and $\ce{Na}$. So could you just use electrolysis until a lot of $\ce{Na}$ was produced then boil off the water? Would the $\ce{O}$ bond to the $\ce{Na}$ to produce $\ce{Na2O}$? If it would make sodium oxide then how difficult would it be to remove the $\ce{O}$ to get just the sodium?

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As someone mentioned in his/her answer last year, you cannot get sodium metal from electrolysis of aqueous sodium chloride. But, contrary to his/her explanation, you do actually get metallic sodium at the cathode in this reaction. Even if the half-cells are separated with Nafion (chloralkali process), the elemental sodium produced at the cathode instantly reacts with the water to produce $\ce{NaOH}$ and hydrogen. So, it appears as though it liberates $\ce{NaOH}$ and $\ce{H2}$ from the outset so most people confuse what's actually happening. You literally have ZERO time to capture the metal before it reacts. It's instantaneous. Using a MERCURY cathode will actually capture metallic sodium inside the mercury as an amalgam. But I know of no method of extracting the sodium from the amalgam. I believe that process is also one that produces $\ce{NaOH}$ in the end. You would have to melt the $\ce{NaCl}$ and perform the electrolysis directly on the salt to get free sodium.

I did think about testing a chloralkali cell with the electrodes right up against the Nafion (and holes in the electrodes) and leaving the cathode side dry to see if sodium ions will permeate and give elemental sodium on that side. I doubt it would work though. Both sides probably have to be wet. And we know when there's water on the negative electrode, you'll get $\ce{NaOH}$, not $\ce{Na}$.

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  • $\begingroup$ Filling in: In the old technology the amalgam was reacted catalytically with water in a separate chamber to form NaOH without contacting the anodic products. Now they use a membrane instead of mercury to effect the separation. Pure sodium never was and cannot be extracted from the amalgam, you get intermetallic compounds. $\endgroup$ – Oscar Lanzi Dec 27 '19 at 12:55
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The answer is no.

Electrolysis of a $\ce{NaCl}$ solution produces $\ce{NaOH}$ as a remainder, not $\ce{Na2O}$. Even if Sodium reacted in such a electrolysis, it would react with water to produce $\ce{H2}$ and $\ce{NaOH}$ again.

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Actually, you have some time to collect Na. It will float and if you add oil on tge top of the water, Na will collect there. Then you just have to collect the very small pieces and press it togeather into a bigger piece, which you then store in parafine or something simillar.

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  • $\begingroup$ No, you really don't. $\endgroup$ – matt_black Dec 28 '19 at 15:05

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