electroplating with different electrode and electrolyte

Question

I wanted to make a school project on galvanic cells and I would like to know of I can make electroplating with electrolyte of $\ce{NaCl}$ to plate let's say a spoon with the sodium from the salt but with out sodium anode. my view is that electroplating works when the positively charged $\ce{Na+}$ ions are reduced to $\ce{Na}$ at the cathode so why do we need the cathode to be sodium as long as it can reduce the sodium ions?

Answer 1

Before you start with your experiments, you might want to read about the concept of a standard electrode potential and have a look at some data, particulary for hydrogen, sodium and chlorine.

Can I electrolyze an aqueous solution of sodium chloride?

Yes you can - but you'll be surprised!
That is, unless you you have checked and understood the data in the link given above.

You would then realize that instead of $\ce{Na+}$, protons will be reduced at the cathode while chlorine will be formed by anodic oxidation of $\ce{Cl-}$.

In short: No sodium metal will be formed here.

Can I produce sodium metal by electrolysis of sodium chloride?

Yes, you can - in principle!

But you probably can't in a school project. Electrolysis requires that your medium is electrically conductive. An aqueous $\ce{NaCl}$ solution is, but that won't help you. A block of solid sodium chloride, on the other hand is a lousy conductor. The situation changes dramatically if you can manage to melt the salt. Molten sodium chloride has a high electrical conductivity. The downside is the melting point of $\ce{NaCl}$ - it is around 800 °C. You could add some calcium chloride to lower the melting point of the mixture to ~ 500 °C, but that's still a lot. Probably a bit too hot for a school project.

So, does anybody use this sh*t?

Yes, this is the established way to produce sodium metal using a special setup known as the Downs cell. But remember, this is in industry, and not suitable for a school project ;-)

But I could use a big spoon as an electrode and electroplate it?

No, sorry! Under the conditions of the industrial electrolysis of molten sodium chloride, sodium is formed. But the melting point of sodium metal is just ~ 98 °C. It is a liquid with a lower density than the molten sodium chloride. The liquid sodium metal is collected above the (iron) cathode.

In summary, I suggest that you rethink your school project ;-)