Which of the following statement is correct?

The correct answer is option 4. The anode in a galvanic cell is negatively charged.

Let us evaluate each statement to determine which one is correct:

1. In Cu/Zn cell reduction occurs at the anode

The statement is incorrect. In a galvanic cell (such as the Cu/Zn cell), reduction occurs at the cathode, not the anode. The anode is where oxidation takes place.

2. In a Daniel cell copper is oxidized to copper ions

The statement is incorrect. In a Daniel cell, copper is reduced, not oxidized. Copper ions \((Cu^{2+})\) are reduced to copper metal (Cu) at the cathode, while zinc is oxidized to zinc ions \((Zn^{2+})\) at the anode.

3. A half-cell reaction is one that involves only half a mole of electrolyte

The statement is incorrect. A half-cell reaction refers to either the oxidation or reduction reaction that occurs in one half of the electrochemical cell. It does not refer to the amount of electrolyte, but rather to the half-reactions involved in the cell.

4. The anode in a galvanic cell is negatively charged

The statement is correct. In a galvanic cell (or voltaic cell), the anode is the electrode where oxidation occurs, and it is the source of electrons. Thus, it is negatively charged relative to the cathode.

The correct statement is: The anode in a galvanic cell is negatively charged