Consider the following statements about galvanic cells.
(A) In a galvanic cell, the two portions in which the reduction and the oxidation half reactions occur are called half-cells or redox couples.
(B) When both the electrodes of a galvanic cell dip in the same electrolyte solution, a salt bridge is not required.
(C) Metals like platinum or gold, used as inert electrodes, take part in the electrode reaction besides providing their surface for oxidation or reduction.
(D) The potential difference between the two electrodes of a galvanic cell is called the emf of the cell when no current is drawn through the cell.
Which of the statements given above are correct? Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (A), (B) and (D) only
A galvanic cell is made of two half-cells, each a metallic electrode dipped in an electrolyte. The half reactions occur in these two portions, and the cell potential is read across the two electrodes.
(A) In a galvanic cell, the two portions in which the reduction and the oxidation half reactions occur are called half-cells or redox couples. — True. In the Daniell cell, the copper electrode is the reduction half-cell and the zinc electrode the oxidation half-cell.
(B) When both the electrodes of a galvanic cell dip in the same electrolyte solution, a salt bridge is not required. — True. A salt bridge connects the electrolytes of two half-cells; with one common electrolyte there is nothing to connect.
(C) Metals like platinum or gold, used as inert electrodes, take part in the electrode reaction besides providing their surface for oxidation or reduction. — False. Inert electrodes do not participate in the reaction; they only provide their surface for oxidation or reduction and for the conduction of electrons, as Pt does in the hydrogen electrode.
(D) The potential difference between the two electrodes of a galvanic cell is called the emf of the cell when no current is drawn through the cell. — True. This potential difference is the cell potential; it is called the cell electromotive force (emf) when no current is drawn.
NCERT (2026-27 edition):
2.2 Galvanic Cells – “…The reduction half reaction occurs on the copper electrode while the oxidation half reaction occurs on the zinc electrode. These two portions of the cell are also called half-cells or redox couples.”
“…Sometimes, both the electrodes dip in the same electrolyte solution and in such cases we do not require a salt bridge.”
“The potential difference between the two electrodes of a galvanic cell is called the cell potential and is measured in volts. The cell potential is the difference between the electrode potentials (reduction potentials) of the cathode and anode. It is called the cell electromotive force (emf) of the cell when no current is drawn through the cell.”
2.2.1 Measurement of Electrode Potential – “…Sometimes metals like platinum or gold are used as inert electrodes. They do not participate in the reaction but provide their surface for oxidation or reduction reactions and for the conduction of electrons.”