Question
The correct statement(s) related to processes involved in the extraction of metals is(are)
JEE Advanced
Chemistry
General Principles and Processes of Isolation of Metals
2023
JEE Advanced 2023 (Paper 1)
JEE Advanced Chemistry Question (2023) — Solution
Options
- A. Roasting of Malachite produces Cuprite
- B. Calcination of Calamine produces Zincite
- C. Copper pyrites is heated with silica in a reverberatory furnace to remove iron
- D. Impure silver is treated with aqueous KCN in the presence of oxygen followed by reduction with zinc metal
Answer
D. Impure silver is treated with aqueous KCN in the presence of oxygen followed by reduction with zinc metal
Step-by-step solution
The ore Calamine contain ZnCO 3 . The Calamine on heating produces ZnO . ZnCO 3 → ∆ ZnO + CO 2 Cyanide process, also called Macarthur-forrest Process, method of extracting silver from impure ores by dissolving them in a dilute solution of sodium cyanide in the presence of oxygen. The complex formed in the above process reduced to silver metal by the treatment with zinc. O 2 + H 2 O + Ag + NaCN → Na Ag CN 2 + NaOH Na Ag CN 2 → Zn Na 2 Zn CN 4 + Ag SiO 2 (Silica) is a flux material. It removes impurities as slag. Here, slag consists of Iron in Sulphide ore of Cu , here impurity is FeO . FeO + SiO 2 → FeSiO 3 Malachite green is CuCO 3 . Cu OH 2 and cuprite is Cu 2 O . The ore malachite green on heating gives cupric oxide but not cuprous oxide. CuCO 3 . Cu OH 2 → ∆ 2 CuO + CO 2 + H 2 O
Related: Chemistry — General Principles and Processes of Isolation of Metals · All PYQ Banks