JEE Main202229 Jun 2022Morning ShiftChemistryGeneral Principles and Processes of Isolation of MetalsActual
In isolation of which one of the following metals from their ores, the use of cyanide salt is commonly not involved?
Options
- AZinc
- BSilver
- CGold
- DCopper
Correct answer
D. Copper
Step-by-step solution
For ZnS , KCN is used as depressant. In the metallurgy of silver and gold, the respective metal is leached with a dilute solution of NaCN or KCN in the presence of air, which supplies O 2 . The metal is obtained later by replacement reaction. 4 M s + 8 CN - aq + 2 H 2 O aq + O 2 g → 4 M CN 2 - aq + 4 OH - aq   M = Ag   or   Au 2 M CN 2 - aq + Zn s → Zn CN 4 2 - aq + 2 M s Copper metal is not involved in this process.