Question

The copper and aluminum electrodes are connected in a battery.

Answer 1

a. Which is the anode?

Al is more reactive than the Cu, because the reduction potential of Al is -1.676 V, so would turn to ions easily hence it would give electrons and form a cation and so it will be the anode.

 

b. Which is oxidized?

Copper is the cathode, because of its reduction potential +0.34 V, which has a higher affinity for electrons and so it will be the oxidizing agent which means the Al is oxidized.  

c. What will the battery voltage be?

The voltage of the battery we can be calculated by using the reduction potentials of both elements:

E°battery = E°cathode - E°anode = E°Cu - E°Al = 0.34 - (-1.676) = 2.016 V

The cell have a spontaneous reaction because the voltage has a positive sign.

d. Write a balanced net ionic equation for the reaction that takes place.  

Al + 3 Cu⁺ ----> Al³⁺ + 3 Cu