Match List-I with List-II.
| List-I (Cell) | List-II (Cathode of the cell) |
|---|---|
| (A) Leclanche cell (dry cell) | (I) Grid of lead packed with lead dioxide |
| (B) Mercury cell | (II) Paste of HgO and carbon |
| (C) Lead storage battery | (III) Porous carbon electrode through which oxygen is bubbled |
| (D) H2–O2 fuel cell | (IV) Carbon (graphite) rod surrounded by powdered manganese dioxide and carbon |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → A-IV, B-II, C-I, D-III
In every one of these cells the cathode is the electrode where reduction takes place, so it carries the substance that takes up electrons.
(A) Leclanche cell (dry cell) — This matches (IV) Carbon (graphite) rod surrounded by powdered manganese dioxide and carbon. The zinc container is the anode; MnO2 is reduced, manganese going from +4 to +3:
\( \ce{MnO2 + NH4+ + e^- -> MnO(OH) + NH3} \)
(B) Mercury cell — This matches (II) Paste of HgO and carbon. The anode is zinc–mercury amalgam; HgO is reduced to liquid mercury:
\( \ce{HgO + H2O + 2e^- -> Hg(l) + 2OH^-} \)
(C) Lead storage battery — This matches (I) Grid of lead packed with lead dioxide. PbO2 is reduced to PbSO4 during discharge; the anode is lead.
(D) H2–O2 fuel cell — This matches (III) Porous carbon electrode through which oxygen is bubbled. Hydrogen is oxidised at the other carbon electrode; oxygen is reduced at this one:
\( \ce{O2(g) + 2H2O(l) + 4e^- -> 4OH^-(aq)} \)
NCERT (2026-27 edition):
2.6.1 Primary Batteries – “…The cell consists of a zinc container that also acts as anode and the cathode is a carbon (graphite) rod surrounded by powdered manganese dioxide and carbon …”
“…Mercury cell, … suitable for low current devices like hearing aids, watches, etc. consists of zinc – mercury amalgam as anode and a paste of HgO and carbon as the cathode.”
2.6.2 Secondary Batteries – “…It consists of a lead anode and a grid of lead packed with lead dioxide (PbO2) as cathode.”
2.7 Fuel Cells – “…In the cell, hydrogen and oxygen are bubbled through porous carbon electrodes into concentrated aqueous sodium hydroxide solution.” … “The electrode reactions are given below: Cathode: O2(g) + 2H2O(l) + 4e– → 4OH–(aq) Anode: 2H2(g) + 4OH–(aq) → 4H2O(l) + 4e–”