Is the decomposition of iron(2) sulphate an endothermic reaction?If yes,why?

Asked by  | 19th May, 2008, 02:44: PM

Expert Answer:

Dear Student,

Iron(II) sulphate is normally found in its hydrated form, FeSO4.7H2O
On gentle heating this green solid turns white as the water of crystallisation is evolved as steam:
FeSO4.7H2O(s) -> FeSO4(s) + 7H2O(l)
On stronger heating the anhydrous white solid darkens as iron(III) oxide is formed. Sulphur dioxide and sulphur trioxide are evolved during this decomposition:
FeSO4(s) -> Fe2O3(s) + SO2(g) + SO3(g)
Notice that this second stage involves redox as well as thermal decomposition.Now as the decomposition takes place only if we apply the heat and not in situ,hence the reaction in endothermic.

Answered by  | 13th Jun, 2008, 07:29: PM

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