Trigger for a Zn oxidation reaction in a battery

[Slava]

Who is the trigger of the oxidation reaction. Copper which attracts electrons from the Zinc or solution which makes Zinc losing electrons and become positively charged. I am struggling to understand what actually makes Zinc to enter the solution and leave 2 electrons behind.

If there is no wire between positive and a negative electrode of a battery Zn won't be able to give away 2 electrons or ZN electrode will still be able to gain a negative charge due to reaction with the solution.

Thank you guys

 

[Drakkith]

I believe that an electric field is built up as zinc reacts with the solution until the electric field prevents any further reactions.
See here: http://en.wikipedia.org/wiki/Half-cell

 

[Slava]

Do I understand it properly. When we electrically connect copper electrode and the zinc electrode the difference in potential between the two will create an electric field or the electric field is produce when zinc is losing electrons while touching the sulphate and copper gains extra electrons.

 

[Slava]

What will happen at the beginning when the copper to the zinc via a conductor without having solutions just two separate pieces of metal connected with a wire. Will zinc lose it valence electrons and copper gain them in this case? Thanks

 

[Drakkith]

Do I understand it properly. When we electrically connect copper electrode and the zinc electrode the difference in potential between the two will create an electric field or the electric field is produce when zinc is losing electrons while touching the sulphate and copper gains extra electrons.

When you first insert the electrode into the solution a chemical reaction between the zinc and the solution takes place. This builds up an electric field since zinc ions are leaving the electrode while leaving behind their electrodes. This buildup of electrons creates an electric field that slows and then stops further reactions. Once you complete the circuit and both electrodes are connected, electrons flow and allow the continuation of the reactions between the zinc and the solution.

What will happen at the beginning when the copper to the zinc via a conductor without having solutions just two separate pieces of metal connected with a wire. Will zinc lose it valence electrons and copper gain them in this case? Thanks

That I couldn't tell you.

 

[Slava]

Why does Zn atoms go to the solution? I am trying to find the reaction which takes place in a half-sell but with no success. I suppose there should be some reaction between
Zn atom and the solution but there is nothing written about. Every textbook shows the whole redox reaction but not the half of it.

Why electrons stay on the electrode rather then jump into the solution. They are repelled by water molecules?

Thank you for your responses

 

[Slava]

I understand that somehow Zinc atoms will dissolve and give up 2 electrons which go into a wire. But what makes them to enter the solution, basically to fall into it?

 

[Drakkith]

They don't just 'fall' into the solution. The reaction occurs where the zinc and the solution meet.

Why electrons stay on the electrode rather then jump into the solution.

I'd need to get into the details of the reaction, which I don't have time to do right now, sorry.

 

[Slava]

As far as I understand. To get the solution we mix sulphate and a water and get an aqueues solution with lots of cations and anions.
ZnSO4 + H2O ---> Zn2+ + SO42- + H2O ---> Zn2+ + HSO4- + OH-

This is the solution. Which ions react with Zn to make it dissolve in the solution?

 

[Slava]

Does zinc react with Hydrogen ions and becomes oxidized?

Zn(s) + 2H+ -> Zn2+(aq) + H2(g)