Q28 / 160 · TS EAMCET 2018 (04 May Shift 2) · Chemistry

The oxidising and reducing agents respectively for the cyanide extraction of silver from argentite ore are

  • A
    $\mathrm{O}_2, \mathrm{CO}$
  • B
    $\mathrm{HNO}_3, \mathrm{CO}$
  • C
    $\mathrm{O}_2, \mathrm{Zn}$ dust
  • Correct answer
    D
    $\mathrm{HNO}_3$, Zn dust

Solution

$\mathrm{Ag}+\mathrm{CN}^{-}(a q)+\mathrm{H}_2 \mathrm{O}+\mathrm{O}_2 \longrightarrow \left[\mathrm{Ag}\left(\mathrm{CN}_2\right)^{-} a q+\mathrm{Zn}(s) \longrightarrow \mathrm{Ag}(s)+\left[\mathrm{An}(\mathrm{CN})_2 \Gamma(a q)+\mathrm{CN}_4\right)\right]^{2-}(a q)$ So, for the extration of $\mathrm{AgO}_2$ act as oxidising agent and $\mathrm{Zn}$ dust act as reducing agent.

Hence, the correct answer is option: 'D'.

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