Extraction of Metals - Result Question 53
Passage
Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper include chalcanthite $\left(\mathrm{CuSO}_4 \cdot 5 \mathrm{H}_2 \mathrm{O}\right)$, atacamite $\left(\mathrm{Cu} _2 \mathrm{Cl}(\mathrm{OH})_3\right)$, cuprite $\left(\mathrm{Cu}_2 \mathrm{O}\right)$, copper glance $\left(\mathrm{Cu}_2 \mathrm{~S}\right)$ and malachite $\left(\mathrm{Cu}_2(\mathrm{OH})_2 \mathrm{CO}_3\right)$. However, $80 %$ of the world copper production comes from the ore chalcopyrite $\left(\mathrm{CuFeS}_2\right)$. The extraction of copper from chalcopyrite involves partial roasting, removal of iron and self-reduction.
(2010)
53. In self-reduction, the reducing species is
(a) $S$
(b) $O^{2-}$
(c) $S^{2-}$
(d) $SO _2$
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Answer:
Correct Answer: 53. (c)
Solution:
- $Cu _2 S+2 Cu _2 O \longrightarrow 6 Cu+SO _2$
In $Cu _2 S$, sulphur is $S^{2-}$ and in $SO _2$, sulphur is in +4 state.
Hence, $S^{2-}$ is acting as reducing agent.
BETA
