Chemical Electric CELL with graphite electrodes?

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matthew77ask
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In normal chemical cells, the electrodes are two different metals so that the more reactive one gives off electrons and create a flow of electrons and hence electricity. [the electrolyte is say NaOH aq or whatever]

Just wondering - is it possible to have a chemical cell consisting of:
a) Copper / graphite electrodes
b) Zinc / graphite electrodes

The metal in the above - can they give off electrons and becomes ion and create a flow of electrons / electricity?

thanks
 
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matthew77ask said:
In normal chemical cells, the electrodes are two different metals

No. Electrodes can be made of metal that dissolves, but they don't have to, they can be inert as well.
 
Borek said:
No. Electrodes can be made of metal that dissolves, but they don't have to, they can be inert as well.

Thanks. If that is the case, can the combination work?

Cu/Graphite; and

Zn/ Graphite

and which is the + terminal and - terminal?

Many thanks
 
I know about how for Mg/Fe cell : -the Mg is more reactive than Fe so gives off electrons and hence becomes the negative electrode.

However, I am confuse with

Cu/Graphite; and

Zn/ Graphite

Because one is metal while the other is not - but just a conductor of electricity.

My guess is that
Cu/Graphite would not work as Graphite is "more reactive" than Cu.

but Zn / Graphite works as Zn is more reactive than Graphite and hence can give off electrons and oxidizes to Zn ion, and becomes the negative terminal.

I Googled - but could not find info on Carbon electrode with Metal as a cell (or maybe the search engine not good enough?)

Am I right? if not please help...

There must be more information that is beyond the O level (which I am teaching) that I may not know of...

Many thanks
 
I am not sure what you mean by Cu/graphite - solid Cu and graphite, or Cu2+ and graphite? For the cell (galvanic) to work you need two half reactions. One must be reduction, the other one oxidation. Having just a solution of cation may give you system ready for reduction, but what is going to be oxidized? Try to write reaction equations.
 
Borek said:
I am not sure what you mean by Cu/graphite - solid Cu and graphite, or Cu2+ and graphite? For the cell (galvanic) to work you need two half reactions. One must be reduction, the other one oxidation. Having just a solution of cation may give you system ready for reduction, but what is going to be oxidized? Try to write reaction equations.

Sorry, I was not clear...

What I really wanted to find out is :
In chemical Cells - if the electrodes are Copper (solid) and Graphite (instead of the usual cells with two different metals) in a electrolyte of aq NaOH, will it works?

What about if it is Magnesium(solid) and Graphite instead - in the same settings.

I was wondering - the cells work on redox. In Cu / Mg electrodes cell, the more reactive metal Mg oxidizes and gives off electrons and becomes the negative terminal, the electrons than travels to Cu electrode and forms a close circuit with the aq NaOH. and the cell is functioning.

In Copper / Graphite [and Magnesium / Graphite] case mentioned, Graphite is not part of the metal reactivity series. And hence with the Graphite oxidizes and gives off electrons ? It most likely not - as what ions will Graphite form? Then, will the set up actually works?

Would it work for Magnesium / Graphite electrode case? Mg is more reactive, hence oxidises and becomes negative electrode, the electrons then travels to the Graphite electrode into the aq NaOH to form a close circuit... would this be correct way of reasoning?

Very interesting - juz that I do not have a lab to just try it out and confirm if the set up can work or not ?

Anyone can help?

Many thanks...
 
Sorry to say that, but you are wrong in so many ways at the same time I have no idea where to start. You really need a solid course in electrochemistry, and some refresher in general chemistry.

Copper is incompatible with NaOH as electrolyte - you will precipitate hydroxide, leaving no Cu2+ in the solution.

Magnesium is a bad idea as well - it is reactive enough to react directly with water, regardless of whether there is copper present or not.

You don't need electrode to reduce or oxidize - while it is one of ways of preparing galvanic cell, it can as well contain system like - say - Ce3+/Ce4+.

You are right about carbon not producing any ions. It doesn't mean there can't be a reaction taking place on its surface.
 
Borek said:
Sorry to say that, but you are wrong in so many ways at the same time I have no idea where to start. You really need a solid course in electrochemistry, and some refresher in general chemistry.

Copper is incompatible with NaOH as electrolyte - you will precipitate hydroxide, leaving no Cu2+ in the solution.

Magnesium is a bad idea as well - it is reactive enough to react directly with water, regardless of whether there is copper present or not.

You don't need electrode to reduce or oxidize - while it is one of ways of preparing galvanic cell, it can as well contain system like - say - Ce3+/Ce4+.

You are right about carbon not producing any ions. It doesn't mean there can't be a reaction taking place on its surface.

You are right - I do need an in solid course in electrochemistry.
When I came up with the combinations - my focus is on the graphite electrodes - and the rest of the components was "done in a fly". Thank you for pointing these out like the Cu2+ with NaOH - did not think of that..(now I learn to look deeper again) and about Magnesium with water.

I have learn a lot in your answers.. thanks a lot.

I still am puzzle - can there be a cell with graphite as one electrode and another metal as the other electrode and what would the combination be for that (electrodes , electrolytes etc) ... many thanks for helping me to answer this question