Electrochemistry Beginner Questions

Sup guys,

I am going to ask a few basic questions here regarding electrochemistry (A2 Chemistry). Please bear with me.

(I am using " →" to represnt reversible reactions)

1. Anode is considered positive through which electrons leave an electrolyte. Two half-cells: anode made of zinc dipped into a solution of a zinc compound containing zinc ion of 1M and the other one is copper electrode dipped into 1M of copper ion solution. They are connected. Oxidation occurs at anode and reduction occurs at cathode.

Zinc is getting oxidised to zinc ion,

Zn → Zn(2+) + 2e-

What happens to this zinc ion and the electrons produced?

Cu(2+) + 2e- → Cu

Is it the copper ion from the solution or from the cathode? Where is it coming from? :confused:

2. Rechargeable Batteries,

In lead-acid batteries,

Anode reaction:

Pb + SO4(2-) → PbSO4 + 2e-

Cathode reaction:

PbO2 + 4H(+) + SO4(2-) + 2e- → PbSO4 + 2H2O

Can someone explain these two reactions? Where did SO4(2-) come from in the cathode reaction?

Thanks. :smile:

Original post by airheadbuster

Sup guys,

I am going to ask a few basic questions here regarding electrochemistry (A2 Chemistry). Please bear with me.

(I am using " →" to represnt reversible reactions)

1. Anode is considered positive through which electrons leave an electrolyte. Two half-cells: anode made of zinc dipped into a solution of a zinc compound containing zinc ion of 1M and the other one is copper electrode dipped into 1M of copper ion solution. They are connected. Oxidation occurs at anode and reduction occurs at cathode.

Zinc is getting oxidised to zinc ion,

Zn → Zn(2+) + 2e-

What happens to this zinc ion and the electrons produced?

The zinc ions wander off into the solution

The electrons go off around the external circuit to the cathode where they are used for the reduction reaction.

Cu(2+) + 2e- → Cu

Is it the copper ion from the solution or from the cathode? Where is it coming from? :confused:

The copper ions migrate to the electrode from the solution.

2. Rechargeable Batteries,

In lead-acid batteries,

Anode reaction:

Pb + SO4(2-) → PbSO4 + 2e-

Cathode reaction:

PbO2 + 4H(+) + SO4(2-) + 2e- → PbSO4 + 2H2O

Can someone explain these two reactions? Where did SO4(2-) come from in the cathode reaction?

Thanks. :smile: