General Questions | JEE 2012 | Discussion Page

In the cyanide extraction process of silver from argentite ore' the oxidizing and reducing agents used are

$O_{2}$ and CO respectively

$O_{2}$ and Zn dust respectively

$HNO_{3}$ Zn dust respectively

$HNO_{3}$ and CO respectively

Option B

The reactions involved in the extraction of silver by the cyanide process are

$Ag_{2}S+CN^{-}+O_{2} \rightarrow [Ag(CN)_{2}]^{-}+SO_{2}$ ..................(i)

$[Ag(CN)_{2}]^{-}+Zn \rightarrow [Zn(CN)_{4}]^{2-}$ +Ag ..........(ii)

In reaction (i), sulphide is oxidized to SO₂ by oxygen. In the reaction (ii),

Silver ion ( $Ag^{+}$ ) is reduced to Ag by Zn.

Therefore, $O_{2}$ . is oxidisinS agent and Zn is reducing agent.

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