Titration of ammonium iron(II) sulphate and potassium managanate
Data Collection
Table 1: Uncertainty of equipment
Table 2: Mass of ammonium iron(II) sulphate
Table 3: Titration of ammonium iron(II) sulphate and potassium managanate (VII)
Colour change of the indicator: colourless to pink ( quantitative observation)
Volume of ammonium iron(II) sulphate used in pipette= 25.00 cm3 ± 0.03 cm3
Volume of ammonium iron(II) sulphate prepared in volumetric flask= 250 cm3 ± 0.3 cm3
Data processing
Average volume of potassium managanate(VII) used
=
=12.40cm3± 0.10 cm3
Redox equation for the reaction.
5Fe2+ +MnO4-+8H+→ 5Fe3+ + Mn2+ + 4H2O
No. Of moles of ammonium iron(II) sulphate used
= Mass/ Mr((NH4)2.Fe(SO4)2.6H2O)= 9.8/332.19=0.02950
Concentration of ammonium iron ...
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Table 3: Titration of ammonium iron(II) sulphate and potassium managanate (VII)
Colour change of the indicator: colourless to pink ( quantitative observation)
Volume of ammonium iron(II) sulphate used in pipette= 25.00 cm3 ± 0.03 cm3
Volume of ammonium iron(II) sulphate prepared in volumetric flask= 250 cm3 ± 0.3 cm3
Data processing
Average volume of potassium managanate(VII) used
=
=12.40cm3± 0.10 cm3
Redox equation for the reaction.
5Fe2+ +MnO4-+8H+→ 5Fe3+ + Mn2+ + 4H2O
No. Of moles of ammonium iron(II) sulphate used
= Mass/ Mr((NH4)2.Fe(SO4)2.6H2O)= 9.8/332.19=0.02950
Concentration of ammonium iron (II) sulphate solution in mol dm-3.
=mole/ volume = 0.02950/ 250 x10-3
= 0.118 mol dm-3
No.of moles of ammonium iron(II) sulphate used for titration
0.118 mol dm-3 x 25cm3x10-3= 2.95x10-3 mol
Mole ratio of Fe2+: MnO4-=5
No.of moles of potassium manganate(VII)
2.95x10-3 mol / 5 = 5.9x10-4 mol
Concentration of potassium managanate(VII) in mol dm-3
5.9x10-4 mol/ 12.40cm3x10-3= 4.76 x10-2mol dm-3
Total uncertainty of apparatus
Uncertainty of conc of potassium manganate(VII) =0.0476Mx2.07%
=0.001 M
Conclusion:
Concentration of potassium manganate(VII) in mol dm-3=0.048±0.001 M
