How much iron is in an iron tablet?

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How much iron is in an iron tablet?

• Group members Choi Chuen Ching (5)
• Fong Ka Yee (6)
• Leung Chi Lai (12)
• Lui Lai Sin (16)

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Aim

• To investigate how much iron is in iron
  tablets.
• 2. To compare the percentage of iron in iron
  tablets from two different manufacturer.
• 3. To find out which one is worth buying.

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Why iron is essential to our body?
the formation of haemoglobin. If we do not have
enough iron in our diet, what will happen? The
deficiency of iron anaemia What can be done if
we suffer from anaemia? consult doctor need to
take iron tablet under the guidance of doctor.
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Principles A. Standardization of Potassium
Permanganate Solution Potassium permanganate
(KMnO4) slowly decomposes in sunlight readily
oxidizes organic matter. ?stored in brown bottle
and has to be standardized before use. Reagents
for the standardization of KMnO4 oxalic
acid sodium oxalates ammonium iron(II)
sulphate arenious oxide. KMnO4 does not
require a chemical indicator for the detection of
end point . Because KMnO4 is deep purple in
color and is reduced to almost colorless solution
(Mn2 salts are light pink in color).
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B. Determination of the mass of iron in one gram
of the iron tablet The iron in iron tablets
comes from hydrated iron(II) sulphate
(FeSO4.7H2O) (sometimes called hydrated ferrous
sulphate). As its name suggests, iron(II)
sulphate contains Fe2 ions. These react with the
MnO4- ions in the potassium permanganate as shown
in the equation below 5Fe2 MnO4 8H
5Fe3 Mn2 4H2O The colour of the potassium
permanganate disappears as it reacts with the
Fe2 ions. This provides a way of deciding when
the titration is complete because, when all the
Fe2 ions are gone, just one drop extra of
potassium permanganate solution will make the
titration mixture turn pale purple.
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Procedures

• A. Standardization of potassium manganate(VII)
  solution
• About 9.8g of ammonium iron(II) sulphate was
  accurately weighed out. Then it was dissolved in
  25ml of sulphuric acid. The mixture was diluted
  with distilled water and was made up to exactly
  250.0ml of solution.
• 25.0ml of this solution was pipetted into a
  conical flask. 25ml of 1M sulphuric acid was
  added to it.
• It was titrated with potassium manganate(VII)
  solution until a permanent pink colour was
  obtained (would not disappear after 30 seconds).
• The molaruty of the manganate(VII) solution was
  calculated.

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B. Determination of the mass of iron in one gram
of the iron tablet 1)  Five iron tablets were
weighed accurately and their masses were
recorded. . 2)  They were grinded up in
a mortar and were pestled with about 5 cm3 of 1M
sulphuric acid.
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3)  The acid and tablets were transferred through
a small filter funnel into a 250.0 cm3 volumetric
flask. The mortar and pestle were rinsed with
further quantities of acid, each portion were
transferred carefully into the flask, until all
trace of the iron tablets had gone.
4)  The funnel was rinsed with more acid, and
then 1M sulphuric acid was added to the flask
until the solution reaches the 250.0 cm3 mark.
The flask was stoppered and was inverted several
times to mix the solution.
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5)   25.0 cm3 of the solution was pipetted from
the volumetric flask and was transferred to a
conical flask. 6)   A burette was filled with the
potassium manganate(VII) solution. 7)   The
potassium manganate(VII) solution was titrated
against the solution in the conical flask. The
volume of potassium manganate(VII) solution used
at the end point was recorded. 8)   The above
steps were repeated but using different brands of
iron tablets in step (1).
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Result
Standardization of potassium permanganate
solution
Trial 1 2 3
Initial/ml 0.10 0.10 0.20 0.00
Final/ml 24.90 25.00 25.00 24.70
Vol. Used/ml 24.80 24.90 24.80 24.70
Average volume used 24.80ml
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Enteric-coated 167mg iron tablets
Weight of 5 tablets 1.067g
Trial 1 2 3
Initial/ml 0.00 3.00 5.70 8.40
Final/ml 3.00 5.70 8.40 11.20
Vol. Used/ml 3.00 2.70 2.70 2.80
Average volume used 2.73ml
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Enteric-coated 300mg iron tablets
Weight of 5 tablets 1.580g
Trial 1 2 3
Initial/ml 0.95 6.45 17.50 22.85
Final/ml 6.45 11.85 22.85 28.25
Vol. Used/ml 5.50 5.40 5.45 5.40
Average volume used 5.42ml
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After calculation, we found that there is
142.76mg of iron present in the 167mg tablet
and 191.42mg of iron present in the 300mg
tablet. Then we decided to remove the coating
of the tablet and see whether the coating will
affect the iron content.
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How about the iron tablets without
enteric-coating?
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167mg iron tablets after removing the
enteric-coat
Weight of 5 tablets 0.959g
Trial 1 2 3
Initial/ml 0.00 2.55 4.90 7.25
Final/ml 2.55 4.90 7.25 9.65
Vol. Used/ml 2.55 2.35 2.35 2.40
Average volume used 2.37ml
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300mg iron tablets after removing the
enteric-coat
Weight of 5 tablets 1.312g
Trial 1 2 3
Initial/ml 36.20 40.70 45.00 39.10
Final/ml 40.60 45.00 49.30 43.40
Vol. Used/ml 4.40 4.30 4.30 4.30
Average volume used 4.30ml
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After calculation, we found that there is
138.48mg of iron present in the 167mg tablet
and 182.88mg of iron present in the 300mg
tablet.
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Discussion
Manufacturer of the iron tablets 167mg tablet
--- Christo Pharmaceutical LTD HK 300mg tablet
--- Apotec Inc.
The table showing the mass of iron present in an
iron tablet
Manufacturer Mass Christo 167mg tablet Apotec 300mg tablet
Tablets with enteric-coating 142.76mg 191.42mg
Tablets without enteric-coating 138.48mg 182.88mg
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It is found that the difference between the
experimental value and the described value of the
Christo is smaller than that of Apotec.
The table showing the of iron present in an
iron tablet
Manufacturer of iron Christo 167mg tablet Apotec 300mg tablet
Tablets with enteric-coating 14.3 19.1
Tablets without enteric-coating 13.9 18.3
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Source of error The iron tablets are not
completely dissolved in sulphuric acid. The
percentage of iron in enteric-coating may not be
the same as that of the inner part of the
tablets. Potassium permanganate may decompose so
that the volume of KMnO4 added may not accurate
enough. The colour of the coating may affect the
observation of end point during titration.
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Observations We found that the 300mg tablet is
more difficult to dissolved in sulphuric
acid. Improvement Potassium permanganate
solution should be used immediately after pouring
out of the brown bottle.
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Conclusion
We found that the difference between the
experimental value and the described value of
167mg tablet was smaller than that of 300mg
tablet. Therefore the manufacturer of 167mg
tablet (i.e.Christo Pharmaceutical LTD HK)is
more reliable than that of 300mg tablet (i.e.
Apotec Inc.). On the other hand, the price of
both kinds of tablets were the same. So 300mg
tablet is more worth buying than 167mg tablet.
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The End