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In the cyanide process, gold is recovered from the leached solution $[Au(CN)_2]^-$ by adding zinc. This recovery step is called
Acalcination
Bcementation
Cliquation
Damalgamation
Answer & Solution
Correct answer: B. cementation
1. Leaching dissolves gold as the complex $[Au(CN)_2]^-$.
2. Adding zinc displaces gold: $Zn + 2[Au(CN)_2]^- \rightarrow [Zn(CN)_4]^{2-} + 2Au$.
3. Recovery of a metal by displacement using a more reactive metal is called **cementation**.
_Source: Samacheer Kalvi Class 12 Chemistry Vol.1, Unit 1 'Metallurgy', §1.2.3 (Cyanide leaching)_
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