Another Galvanic Cell Question (1 Viewer)

[hothand621]

Hey guys, one more question.

Can graphite be reduced in a galvanic cell?

 

[strawberrye]

Graphite is an inert electrode, like other inert electrode such as platinum, it can never be reduced in a galvanic cell.

 

[hothand621]

Ok thanks...
SO what is reduced in a galvanic cell with a zinc electrode half cell in 1.0 M NaCl and a Graphite electrode in 1.0 M NaCl?

 

[anomalousdecay]

Zinc is reduced and Chlorine is oxidised:

 

[hothand621]

Zinc is reduced and Chlorine is oxidised:

But the zinc electrode was connected to the negative terminal therefore the zinc has to be oxidised

 

[anomalousdecay]

But the zinc electrode was connected to the negative terminal therefore the zinc has to be oxidised

If Zinc is oxidised, then only Chlorine can be reduced (using the reduction potentials table). If this is the case, then you would need a gaseous supply of Chlorine gas. Otherwise, Zinc would be reduced as Sodium is oxidised. You need to have more information before deciding on what is happening.

But sorry, my equations are also in a completely wrong context.

 

[hothand621]

If Zinc is oxidised, then only Chlorine can be reduced (using the reduction potentials table). If this is the case, then you would need a gaseous supply of Chlorine gas. Otherwise, Zinc would be reduced as Sodium is oxidised. You need to have more information before deciding on what is happening.

But sorry, my equations are also in a completely wrong context.

Would the H2O in the electrolyte be reduced?

 

[anomalousdecay]

Would the H2O in the electrolyte be reduced?

I doubt it. The NaCl solution is fairly concentrated. I might need someone else's confirmation on this though.

 

[hothand621]

I doubt it. The NaCl solution is fairly concentrated. I might need someone else's confirmation on this though.

But then what is reduced?

 

[anomalousdecay]

But then what is reduced?

The possibilities: Zinc is oxidised, Chlorine gas is reduced or Sodium is oxidised and Zinc/Chlorine gas is reduced.

There is quite a concentrated mixture of NaCl, which means that water will not participate in this reaction.

In essence, if you reverse the bias of the negative and positive terminal, electrolysis will occur if you supply an emf to it. This is out of scope of Production of Materials, and you will come across it if you do Industrial Chemistry or Shipwrecks, Corrosion and Conservation as option modules.