Question

Which of the following ores is concentrated by chemical leaching method?

• A. Cinnabar
• B. Argentite
• C. Copper pyrites
• D. Galena

Answer 1

The correct option is B Argentite

• In the metallurgy of silver , the respective metal is eached with a dilute solution of NaCN or KCN in the presence of air, which supplies $O_2$. The metal is obtained later by replacement reaction.
  
• The reactions involved are-

$4Ag+8C{N}^{-}+2H_{2}O+O_2\to 4\left[M\right(CN{)}_2{]}^{-}+4O{H}^{-}$

$2\left[Ag\right(CN{)}_2{]}^{-}+Zn\to \left[Zn\right(CN{)}_4{]}^{2-}+2Ag$

• Hence, Argentite being an ore of SIlver is concenrated by leaching.