Verified Solution • 2025–26 Session
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QJEEAdv21Ch255c: JEE Advanced 2021 Chemistry - Class 12 JEEAdv21Ch255c Solution: The correct statement(s) related to the metal extraction…
The correct statement(s) related to the metal extraction processes is (are) :
Multiple Choice Options
- A A mixture of PbS and PbO undergoes self-reduction to produce Pb and SO2
- B In the extraction process of copper from copper pyrites, silica is added to produce copper silicate.
- C Partial oxidation of sulphide ore of copper by roasting, followed by self-reduction produces blister copper.
- D In cyanide process, zinc powder is utilized to precipitate gold from Na[Au(CN)2]
Step-by-Step Verified Solution
Statements (a), (c) and (d) are correct, whereas statement (b) is incorrect. All statements are explained as follows :
(a) A mixture PbO and PbS reacts as follows:
This reaction is known as self-reduction.
(b) Silica is added to remove impurities of Fe in the form of slag, FeSiO3 .
(c) CuFeS2 are in partially oxidised first by roasting and then self-reduction of Cu takes place to produce blister copper.
(d) Zn powder reacts with Na[Au(CN)2 ] to form gold. This process is called cyanide process.
2Zn + 4Na[Au(CN)2] → 2Na2[Zn(CN)4]+ 4Au