The cell for the following reaction can be represented asMg (s) + 2Ag…

The correct answer is Option (2) → Mg|Mg²⁺ ||Ag⁺|Ag

In the cell notation, the anode (oxidation) is written on the left and the cathode (reduction) on the right; a single line separates a metal from its solution and a double line stands for the salt bridge. Each half-cell is written in the direction of its change: anode metal | ion, cathode ion | metal.

In the given reaction, magnesium loses electrons and silver ions gain them:

    Anode (oxidation): \( \ce{Mg(s) -> Mg^2+(aq) + 2e^-} \)
    Cathode (reduction): \( \ce{2Ag^+(aq) + 2e^- -> 2Ag(s)} \)

So the cell is represented as Mg|Mg²⁺||Ag⁺|Ag.

Why the other options are incorrect

• Option (1) Ag|Ag⁺ ||Mg²⁺|Mg — Incorrect. This puts silver as the anode, which represents the reverse, non-spontaneous reaction.

• Option (3) Mg²⁺| Mg||Ag|Ag⁺ — Incorrect. Both half-cells are written in the wrong direction (ion | metal at the anode, metal | ion at the cathode).

• Option (4) Ag⁺|Ag ||Mg|Mg²⁺ — Incorrect. The anode and cathode are swapped, and each half-cell is also written the wrong way round.

NCERT (2026-27 edition):
Galvanic Cells – …