(A) In the extraction of gold, the metal is leached with a dilute solution of $NaCN$ in the presence of air (oxygen) to form the complex $X = [Au(CN)_

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$[Au(CN)_2]^-$ and $[Zn(CN)_4]^{2-}$

(A) In the extraction of gold, the metal is leached with a dilute solution of $NaCN$ in the presence of air (oxygen) to form the complex $X = [Au(CN)_2]^-$.Then, gold is recovered by displacement with zinc, which forms the complex $Y = [Zn(CN)_4]^{2-}$.The chemical equations are:$4Au + 8CN^- + 2H_2O + O_2 \rightarrow 4[Au(CN)_2]^- + 4OH^-$$2[Au(CN)_2]^- + Zn \rightarrow [Zn(CN)_4]^{2-} + 2Au$Thus, $X$ is $[Au(CN)_2]^-$ and $Y$ is $[Zn(CN)_4]^{2-}$.

Class 12 Chemistry General Principles and Processes of Isolation of Elements Reduction to free Metal

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Extraction of gold $(Au)$ involves the formation of complex ions $X$ and $Y$ as shown in the reaction: $\text{Gold ore}$ $\xrightarrow{CN^-, H_2O, O_2} HO^- + X$ $\xrightarrow{Zn} Y + Au$. $X$ and $Y$ respectively are:

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A
$[Au(CN)_2]^-$ and $[Zn(CN)_4]^{2-}$
B
$[Au(CN)_4]^{3-}$ and $[Zn(CN)_4]^{2-}$
C
$[Au(CN)_3]^-$ and $[Zn(CN)_6]^{4-}$
D
$[Au(CN)_4]^-$ and $[Zn(CN)_3]^-$

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General Principles and Processes of Isolation of Elements

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Reduction to free Metal

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Extraction of gold $(Au)$ involves the formation of complex ions $X$ and $Y$ as shown in the reaction: $\text{Gold ore}$ $\xrightarrow{CN^-, H_2O, O_2} HO^- + X$ $\xrightarrow{Zn} Y + Au$. $X$ and $Y$ respectively are:

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The Ellingham diagram of a certain metal $M$ is represented in the figure. The points $A$ and $B$ respectively correspond to:

At a site,low grade copper ores are available and zinc and iron scraps are also available. Which of the two scraps would be more suitable for reducing the leached copper ore and why?

Impure silver ore $+ CN^{-} + H_2O \xrightarrow{O_2} [X]^{-} + OH^{-}$$[X]^{-} + Zn \longrightarrow [Y]^{2-} + Ag \text{ (pure)}$The coordination numbers of the metals in $[X]$ and $[Y]$ are respectively

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What is the purpose of adding $Na_3AlF_6$ to $Al_2O_3$ during electrolysis?

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Impure silver ore $+ CN^{-} + H_2O \xrightarrow{O_2} [X]^{-} + OH^{-}$
$[X]^{-} + Zn \longrightarrow [Y]^{2-} + Ag \text{ (pure)}$
The coordination numbers of the metals in $[X]$ and $[Y]$ are respectively