Match List I with List II
| List I | List II |
| (A) Electrolytic reduction | (I) Iron |
| (B) Bessemerisation | (II) Zinc |
| (C) Smelting | (III) Aluminium |
| (D) Reduction from oxide | (IV) Copper |
Choose the correct answer from the options given below:
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
The method used to get a metal from its ore depends on how easily its oxide or sulphide is reduced: very reactive metals need electrolysis, while others are reduced by carbon or by self-reduction of the sulphide.
(A) Electrolytic reduction — This matches (III) Aluminium. \( \ce{Al2O3} \) is too stable to be reduced by carbon; purified alumina dissolved in molten cryolite is electrolysed (Hall–Heroult process).
Cathode: \( \ce{Al^3+(melt) + 3e^- -> Al(l)} \)
Anode: \( \ce{C(s) + O^2-(melt) -> CO(g) + 2e^-} \) and \( \ce{C(s) + 2O^2-(melt) -> CO2(g) + 4e^-} \)\( \ce{2Al2O3 + 3C -> 4Al + 3CO2} \)
(B) Bessemerisation — This matches (IV) Copper. Copper matte is blown with air in a Bessemer converter; \( \ce{Cu2S} \) is partly oxidised and the oxide reduces the remaining sulphide (self-reduction) to blister copper.
\( \ce{2Cu2O + Cu2S -> 6Cu + SO2} \)
(C) Smelting — This matches (I) Iron. Haematite is smelted with coke and limestone in a blast furnace, where CO reduces the oxide.
\( \ce{C + O2 -> CO2} \) and \( \ce{CO2 + C -> 2CO} \)
\( \ce{Fe2O3 + 3CO -> 2Fe + 3CO2} \)(D) Reduction from oxide — This matches (II) Zinc. The roasted ore (ZnO) is heated with coke and the zinc distils off.
\( \ce{ZnO + C} \xrightarrow{\text{673 K}} \ce{Zn + CO} \)
Shortcut: (A)-(III) is in Options (1) and (3); (B)-(IV) then leaves only Option (3).
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.