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Cyanide Process - Practice Questions & MCQ

Edited By admin | Updated on Sep 18, 2023 18:35 AM | #JEE Main

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MEDIUM

The cyanide process is used for the extraction of:

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The silver complex formed during the cyanide process is:

$\begin{aligned} & \mathrm{Na}_2[\mathrm{Ag}(\mathrm{CN})] \\ \end{aligned}$

$\begin{aligned} & \mathrm{Na}[\mathrm{AgCN}] \\ \end{aligned}$

$\begin{aligned} & \mathrm{Na}_2\left[\mathrm{Ag}(\mathrm{CN})_2\right] \\ \end{aligned}$

$\begin{aligned} & \mathrm{Na}\left[\mathrm{Ag}(\mathrm{CN})_2\right] \end{aligned}$

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Gold Cyanidation (Mac-arther forrest process)

The cyanide process, also called the Macarthur-Forrest cyanide Process, method of extracting silver and gold from their ores by dissolving them in a dilute solution of sodium cyanide or potassium cyanide. The process was invented in 1887 by the Scottish chemist John S. MacArthur, Robert W. Forrest, and William Forrest. The method includes three steps:

Contacting the finely ground ore with the cyanide solution.
Separating the solids from the clear solution.
Recovering the precious metals from the solution by precipitation with zinc dust.

$\mathrm{Ag\: +\: NaCN\: +\: H_{2}O\: +\: \:\frac{1}{2}O_{2}\: \rightarrow \: 2Na[Ag(CN)_{2}]\: +\: 2NaOH}$

$\mathrm{2Na[Ag(CN)_{2}]\: +\: Zn\: \rightarrow \: Na_{2}[Zn(CN)_{4}]\: +\: 2Ag\downarrow}$
more electropositive
metal

$\mathrm{2Na[Au(CN)_{2}]\: +\: Zn\: \rightarrow \: Na_{2}[Zn(CN)_{4}]\: +\: 2Au\downarrow}$

NOTE: It is a metallurgical process/technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex