In the extraction of metallic Zn from calamine ore \((ZnCO_3)\) following steps are involved:
(A) Distillation of impure Zn
(B) Calcination of the ore
(C) Hydraulic washing of ore
(D) Reduction of ZnO using coke
Choose the correct order of steps from the options given below:
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → (C), (B), (D), (A)
Zinc is extracted from calamine in the usual metallurgical order: concentration → conversion to oxide → reduction → refining.
(C) Hydraulic washing: the heavier ore particles are separated from the lighter gangue in a stream of water (concentration).
(B) Calcination: the carbonate is heated in limited air and loses \( \ce{CO2} \):
\( \ce{ZnCO3} \xrightarrow{\Delta} \ce{ZnO + CO2} \)(D) Reduction of ZnO with coke (about 1673 K):
\( \ce{ZnO + C} \xrightarrow{\text{coke, 1673 K}} \ce{Zn + CO} \)(A) Distillation: zinc has a low boiling point (1180 K), so the impure metal is refined by distilling it off.
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.