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markosheehan
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A solution of (NH4)2SO4·FeSO4·6H2O (hydrated ammonium iron(II) sulfate), used as a primary
standard, was prepared by dissolving 8.82 g of the crystals in dilute sulfuric acid and making the
solution up to exactly 250 cm3 with deionised water. This standard solution was titrated in
25.0 cm3 portions, to which some more dilute sulfuric acid had been added, with a solution of
potassium manganate(VII) (KMnO4). On average, 20.45 cm3 of the potassium manganate(VII)
solution were required for complete oxidation of the Fe2+ ions.
The equation for the titration reaction is:
MnO4– + 5Fe2+ + 8H+→ Mn2+ + 5Fe3+ + 4H2O (b) Explain why it was necessary
(i) to use dilute sulfuric acid when preparing the standard solution from hydrated
ammonium iron(II) sulfate, why did the sulfuric acid had to be dilute does anyone know?
thanks
standard, was prepared by dissolving 8.82 g of the crystals in dilute sulfuric acid and making the
solution up to exactly 250 cm3 with deionised water. This standard solution was titrated in
25.0 cm3 portions, to which some more dilute sulfuric acid had been added, with a solution of
potassium manganate(VII) (KMnO4). On average, 20.45 cm3 of the potassium manganate(VII)
solution were required for complete oxidation of the Fe2+ ions.
The equation for the titration reaction is:
MnO4– + 5Fe2+ + 8H+→ Mn2+ + 5Fe3+ + 4H2O (b) Explain why it was necessary
(i) to use dilute sulfuric acid when preparing the standard solution from hydrated
ammonium iron(II) sulfate, why did the sulfuric acid had to be dilute does anyone know?
thanks
