Leaching of gold with dilute aqueous solution of NaCN in presence of oxygen gives complex [A], which on reaction with zinc forms the elemental gold and another complex [B]. [A] and [B], respectively are :
Solution
In the metallurgy of gold <br/><br/>
$$4 \mathrm{Au}+8 \mathrm{CN}^{-}+2 \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2} \rightarrow 4\left[\mathrm{Au}(\mathrm{CN})_{2}\right]^{-}+4 \mathrm{OH}^{-}$$<br/><br/>
$$2\left[\mathrm{Au}(\mathrm{CN})_{2}\right]^{-}+\mathrm{Zn} \rightarrow\left[\mathrm{Zn}(\mathrm{CN})_{4}\right]^{2-}+2 \mathrm{Au}$$
About this question
Subject: Chemistry · Chapter: p-Block Elements · Topic: Group 13: Boron Family
This question is part of PrepWiser's free JEE Main question bank. 300 more solved questions on p-Block Elements are available — start with the harder ones if your accuracy is >70%.