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प्रश्न
What happens when Silver is leached with NaCN in the presence of air?
उत्तर
Ag is leached with NaCN in presence of air.
4Ag(s)+ 8CN-(aq) + 2H2O(aq)+ O2(g) → 4[Ag (CN)2]-(aq) + 4OH- (aq)
2[Ag(CN)2]-(aq)+Zn(s) →[Zn(CN)4]2- (aq) + 2Ag(s)
Ag is obtained as solid by leaching process.
संबंधित प्रश्न
Name the common elements present in the anode mud in electrolytic refining of copper. Why are they so present ?
Outline the principles of refining of metals by the following methods: Vapour phase refining
Describe ‘froth floatation process’ for concentration of sulphide ore.
Outline the principles behind the refining of metals by the following methods:
Chromatographic method
In which of the following method of purification, metal is converted to its volatile compound which is decomposed to give pure metal?
(i) Heating with stream of carbon monoxide.
(ii) Heating with iodine.
(iii) Liquation.
(iv) Distillation.
In the extraction of chlorine from brine:
(i) ∆GΘ for the overall reaction is negative.
(ii) ∆GΘ for the overall reaction is positive.
(iii) EΘ for overall reaction has negative value.
(iv) EΘ for overall reaction has positive value.
Why is an external emf of more than 2.2 V required for the extraction of \[\ce{Cl2}\] from brine?
Give two requirements for vapour phase refining.
Match the items of Column I with the items of Column II and assign the correct code:
| Column I | Column II |
| (A) Coloured bands | (1) Zone refining |
| (B) Impure metal to volatile complex | (2) Fractional distillation |
| (C) Purification of Ge and Si | (3) Mond Process |
| (D) Purification of mercury | (4) Chromatography |
| (5) Liquation |
Describe a method for refining nickel.
