Question

In the extraction of copper from its sulphide ore, the metal is finally obtained by the reduction of cuprous oxide with:
A.$S{O_2}$
B.$F{e_2}S{O_3}$
C.$C{u_2}O$
D.$CO$

Answer 1

Hint: To answer this question, you should recall the concept of extraction of metals. The most common ore of copper is chalcopyrite and is used in the extraction of copper.

Complete Step by step solution:
Copper exists in the form of sulphide in the ore. After concentration of the ore, it is heated strongly with silicon dioxide, calcium carbonate and air or oxygen in a furnace or series of furnaces. This results in the copper (II) ions in the chalcopyrite being reduced to copper(I) sulphide. The iron impurities in the ore get converted into an iron (II) silicate slag which is removed.
The other Sulphur impurities are converted into Sulphur dioxide gas. This method is used to produce sulphuric acid via the Contact Process. The final step involves the copper(I) sulphide produced being converted to copper with a final blast of air.
 The reaction can be represented by the equation:
\[C{u_2}S + 2C{u_2}O{\text{ }} \to Cu + {\text{ }}S{O_2}\].
In this reaction the copper(I) sulphide, the oxidation number of copper is $ + 1$ and the oxidation number of Sulphur $ - 2$ . The oxidation states of the element: oxygen in the gaseous state and copper in the metallic state are 0. In Sulphur dioxide, the oxygen has an oxidation state of $ - 2$ and the Sulphur $ + 4$ . In this process \[C{u_2}S\] behaves as a reducing agent and \[C{u_2}O\] an oxidizing agent.

Hence, the correct option is C.

Note: Another method of extraction of copper is electrolytic refining for extraction of copper from its ore. The purification in this method uses an electrolyte of copper (II) sulphate solution, impure copper anodes, and strips of high purity copper for the cathodes. At the cathode, copper (II) ions get deposited as solid copper due to reduction: $C{u^{2 + }} + 2{e^ - } \to Cu(s)$. At the anode, copper gets dissolved in the electrolyte as copper (II) ions $Cu(s) \to C{u^{2 + }} + 2{e^ - }$.