Metallic gold is frequently found in aluminosllicate rocks and it is finely dispersed among other minerals.It may be extracted by treating the crushed
Metallic gold is frequently found in aluminosllicate rocks and it is finely dispersed among other minerals.It may be extracted by treating the crushed rock with aerated potassium cyanide solution.During this process metallic gold is slowly converted to `[An(CN)_2]^(-)` , which is soluble in water.After equilibrium has been reached.the aqueous phase is pumped off and the metallic gold is recovered from it by reacting the gold complex with zinc, which is converted to `[Zn(CN)_4]^(2-)`. Gold in nature is frequently alloyed with silver which is also oxidised by aerated sodium cyanide solution.Silver occurs as native as well as sulphurised ore.
Which of the following statements is correct ?
A. Leaching of gold with `CN^-` is an oxidation reduction
B. Argentite is oxide ore of silver
C. In the precipitation of gold from the soluble complex, zinc acts as complexing and reducing agent
D. (A) and (C ) both
1 Answers
Correct Answer - D
Au `to [Au^+]` which then from complex with `CN^(-)`
`2[Au(CN)_2]+Znto 2Audarr+[Zn(CN)_4]^(3-)`Zinc acts both as complexing and reducing reagent.