- Home
- Standard 12
- Chemistry
General Principles and processes of Isolation of Elements
medium
Extraction of gold and silver involves leaching with $CN^-\, ion.$ Silver is later recovered by
A
distillation
B
zone refining
C
displacement with $Zn$
D
liquation
(NEET-2017)
Solution
Mac arther forest process/cyanide process
$\mathrm{Ag}_{2} \mathrm{S}+4 \mathrm{NaCN} \stackrel{\mathrm{O}_{2}}{\longrightarrow} 2 \mathrm{Na}[\mathrm{Ag}(\mathrm{CN})_2]+\mathrm{Na}_{2} \mathrm{SO}$
$2 \mathrm{Na}[\mathrm{Ag}(\mathrm{CN}),] \stackrel{\mathrm{Zn}}{\longrightarrow} \mathrm{Na}_{2}\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]+\mathrm{Ag}(\downarrow)$
Soluble complex $Ag$ extracts by displacement with $Zn$
Standard 12
Chemistry
