A question regarding electrolysis

[Faiq]

Why does a different reaction occur at anode when electrode isn't inert and has the same metal ion as present in electrolyte?
What will happen if the electrode isn't inert but is formed of a metal which is different than one present in electrolyte?

For example, we know that in electrolysis of silver nitrate with silver electrodes yields a different reaction at anode. My question is why does such a different reaction occurs and what happens if we have a different, non-inert electrode, say for example copper (electrolysis of silver nitrate using copper electrodes) ?

 

[Borek]

Why does a different reaction occur at anode when electrode isn't inert

I have a feeling you have already answered your own question: reaction occurs because the electrode isn't inert.

And you can't expect copper to react as if it was silver. It has to react the way copper does.

 

[Faiq]

I have a feeling you have already answered your own question: reaction occurs because the electrode isn't inert.

And you can't expect copper to react as if it was silver. It has to react the way copper does.

Yeah so what will happen with the copper anode? Will a different reaction occur? If so what reaction?

 

[Borek]

Non-inert anodes get oxidized. Why should the copper behave differently in this case?

 

[Faiq]

In electrolysis of AgNO3, when silver anode is used, instead of anion being liberated at anode (which happens in inert electrodes) we get a reaction which is very different.
Instead of
2O^-+2e^- -> O₂
We get
Ag -> Ag⁺ + e^-

My question is why does the second reaction instead of the usual first reaction occurs, and which reaction will occur if the anode is copper?

 

[Borek]

It depends on the redox systems present and on their formal potentials - the one with the lowest potential will react first. To predict what to expect you need to consult a data table (like this one).