Which of the following is not true of a voltaic cell?

The correct answer is Option (4) → The electrode material itself is oxidised or reduced at both electrodes.

In a voltaic cell, oxidation takes place at the anode and reduction at the cathode, and each electrode dips in an electrolyte. The electrode metal need not take part in the reaction: in the Daniell cell the zinc anode is oxidised, but at the cathode it is the \( \ce{Cu^2+} \) ions of the solution that are reduced, and the copper rod only receives the deposited copper.

    \( \displaystyle \ce{Cu^2+(aq) + 2e^- -> Cu(s)} \)

Option (1) The electrode at which the oxidation takes place is called the anode. — True of a voltaic cell. Oxidation releases electrons at the anode, which is the negative electrode.

Option (2) The electrode at which the reduction takes place is called the cathode. — True of a voltaic cell. The electrons arriving through the wire are taken up at the cathode.

Option (3) The medium in which the electrodes are dipped should be a solution of an electrolyte. — True of a voltaic cell. Each half-cell is a metallic electrode dipped into an electrolyte; the ions carry the current inside the cell.

Option (4) The electrode material itself is oxidised or reduced at both electrodes. — Not true of a voltaic cell. At the cathode of the Daniell cell the ions in solution are reduced, and inert platinum or gold electrodes do not participate in the reaction at all.

NCERT (2026-27 edition):
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.”