Suppose the Cu electrode was replaced by an Al electrode. In order for this new cell to be a galvanic cell, which electrode would be the anode, Zinc or Aluminum?
In order for the cell to be a galvanic cell, the anode should be the electrode where oxidation occurs. Oxidation involves the loss of electrons.
When a zinc electrode reacts in a galvanic cell, it oxidizes to form Zn2+ ions and releases electrons. On the other hand, when an aluminum electrode reacts in a galvanic cell, it does not easily oxidize.
Therefore, if the Cu electrode is replaced by an Al electrode, the Al electrode would be the anode as it would undergo oxidation and lose electrons. The zinc electrode would be the cathode, where reduction occurs.
To determine which electrode would be the anode when the Cu electrode is replaced by an Al electrode, we need to look at the standard reduction potentials of the half-reactions involving zinc (Zn) and aluminum (Al).
The anode is where oxidation occurs, so we are looking for the half-reaction with the lower reduction potential. The standard reduction potentials for the half-reactions are as follows:
Zn2+ + 2e- -> Zn (reduction potential: -0.7618 V)
Al3+ + 3e- -> Al (reduction potential: -1.662 V)
Since the reduction potential of the Al half-reaction is lower than that of the Zn half-reaction, aluminum (Al) will be the anode. Therefore, in the galvanic cell, aluminum will undergo oxidation and act as the anode, while zinc (Zn) will be the cathode.