Question

Which of the following reactions represents the self-reduction process?

• A. $\left\{ \begin{array} { l } \mathrm { HgS } + \mathrm { O } _ { 2 } \rightarrow \mathrm { HgO } + \mathrm { SO } _ { 2 } \\ \mathrm { HgO } + \mathrm { HgS } \rightarrow \mathrm { Hg } + \mathrm { SO } _ { 2 } \end{array} \right.$
• B. $\left\{ \begin{array} { l } \mathrm { Cu } _ { 2 } \mathrm {~S} + \mathrm { O } _ { 2 } \rightarrow \mathrm { Cu } _ { 2 } \mathrm { O } + \mathrm { SO } _ { 2 } \\ \mathrm { Cu } _ { 2 } \mathrm {~S} + \mathrm { Cu } _ { 2 } \mathrm { O } \rightarrow \mathrm { Cu } + \mathrm { SO } _ { 2 } \end{array} \right.$
• C. $\left\{ \begin{array} { l } \mathrm { PbS } + \mathrm { O } _ { 2 } \rightarrow \mathrm { PbO } + \mathrm { SO } _ { 2 } \\ \mathrm { PbO } + \mathrm { PbS } \rightarrow \mathrm { Pb } + \mathrm { SO } _ { 2 } \end{array} \right.$
• D. All of these

Answer 1

Answer: (D)

All of these

Answer 2

Sulphide ore of Hg, Cu, Pb are heated in air, a part of these is changed in to oxides or sulphate that then react with the remaining part of the sulphide ore to give its metal and SO2. This is called self reduction, auto reduction or air reduction method.