Experiment 4: Analysis of an iron tablet

To analyse for the iron content of a pharmaceutical iron replacement tablet.

Notes

Potassium manganate (VII) is a self indicating reagent for titrations. It will oxidise iron II to iron III according to the equation:

MnO4- + 5Fe2+ + 8H+ Mn2+ + 5Fe3+ + 4H2O

Consequently the ratio is one mole of manganate VII ions are equivalent to 5 moles of Fe2+ ions

Instructions

The students should extract the contents of a weighed iron tablet by boiling with dilute sulphuric acid. it may be necessary to add activated charcoal before filtering to remove the colour of any dyestuffs present.

If the resultant solution is made up to a known volume then it should be possible to proceed as per experiment 3.

Experimental report

The following factors must be considered:

• Accurate recording of raw data
• Choice of suitable apparatus and method
• Presentation of raw data
• Data analysis and presentation
• Evaluation of errors both qualitative and numerical

Assessment

• Data collection
• Planning (b)
• Data analysis
• Evaluation