IIT-JEE 2010 · Paper 1 · Chemistry Q16

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ChemistrySingle correct+3 / -1Question 16 of 84

Passage

Paragraph for Questions 14 to 16

Copper is the most noble of the first row transition metals and occurs in small deposits in several countries. Ores of copper include chalcanthite ( $\ce{CuSO4.5H2O}$ ), atacamite ( $\ce{Cu2Cl(OH)3}$ ), cuprite ( $\ce{Cu2O}$ ), copper glance ( $\ce{Cu2S}$ ) and malachite ( $\ce{Cu2(OH)2CO3}$ ). However, 80% of the world copper production comes from the ore chalcopyrite ( $\ce{CuFeS2}$ ). The extraction of copper from chalcopyrite involves partial roasting, removal of iron and self-reduction.

In self-reduction, the reducing species is

\ce{O^{2-}}

\ce{S^{2-}}

\ce{SO2}

Answer and worked solution

Official answer: C

Self-reduction (in the Bessemer converter): part of the $\ce{Cu2S}$ is oxidised to $\ce{Cu2O}$ , which then reacts with the remaining sulphide:
$\ce{2Cu2O + Cu2S -> 6Cu + SO2}.$
Copper(I) is reduced to Cu(0), and sulphur goes from −2 to +4. The reducing species is the sulphide ion, $\ce{S^{2-}}$ .

(C)

Topics:Extraction of specific metals Oxidation number

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IIT-JEE 2010 · Paper 1, Chemistry question 16