AIEEE 2008 Solved Paper

NOTE : The reduction of metal sulphides by carbon reduction process is not spontaneous because ∆G for such a process is positive. The reduction of metal oxide by carbon reduction process is spontaneous as ∆G for such a process is negative.
From this we find that on thermodynamic considerations CO2 is more stable than CS2 and the metal sulphides are more stable than corresponding oxides.
In view of above the factor listed in choice (c) is incorrect and so is of no significance.