Which of the following factors is of no significance for roasting sulphide ores to the oxides and not subjecting the sulphide ores to carbon reduction directly?

  • Option 1)

    CO_{2} is more volatile than  CS_{2}

  • Option 2)

    Metal sulphides are thermodynamically more stable than CS_{2}

  • Option 3)

    CO_{2} is thermodynamically more stable than  CS_{2}

  • Option 4)

    Metal sulphides are less stable than the corresponding oxides

 

Answers (1)
P Prateek Shrivastava

As we learnt in

Roasting -

It is heating of the ore in presence of air below its fusion temperature.

- wherein

2PbS +3O3 \rightarrow 2PbO + 2SO2

 

The reduction of metal sulphides by carbon reduction has positive  \Delta G whereas, \Delta G is negative for the same process with metal oxides. So, metal sulphides are more stable than oxides. 

 


Option 1)

CO_{2} is more volatile than  CS_{2}

This option is incorrect.

Option 2)

Metal sulphides are thermodynamically more stable than CS_{2}

This option is incorrect.

Option 3)

CO_{2} is thermodynamically more stable than  CS_{2}

This option is incorrect.

Option 4)

Metal sulphides are less stable than the corresponding oxides

This option is correct.

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