PAG 1.2 - Investigating iron tablets.
10/03/2025
Research (introduction):
● Iron tablets are also known as Ferrous Sulphate Tablets (an iron salt of iron tablets
with the chemical formula FeSO4), the tablets contain iron which is an essential
mineral in red blood cell production. It is often prescribed to treat people who have an
iron deficiency in the diet or body, this is known as anaemia (telgurus: what do iron
tablets contain?). Each Ferrous sulfate tablet has a mass of 200 mg which is
equivalent to 65 mg ferrous iron (emc: Ferrous Sulfate tablets 200 mg). The
recommended daily intake of iron in general, varies depending on age and gender.
For men, 19 and above need around 8.7 mg a day. In comparison, women aged
19-49 require 14.8 mg a day, whereas those aged 50 and above (post-menopausal)
need around 8.7 mg just like men. However, if menstruation is still occuring after the
age of 50 then the amount will rise to 14.8 mg. This is due to the woman's monthly
period and losing iron in the blood, so those with more heavy periods are at a higher
risk of iron deficiency anaemia and may need to take iron tablets (NHS: Vitamins
and minerals - iron). The manganate (VII) is reduced to Mn2+ (it accepts electrons).
These electrons are provided by Fe (II) ions which act as the reducing agent. The
potassium manganate (VII) is immediately decolourised when added to the solution
of the reducing agent, then when the reducing agent is used up the potassium
manganate (VII) colours the solution a pale pink colour -> it is self-indicating so does
not require any universal indicator (practical science: titration - redox iron tablet).
References:
● https://telgurus.co.uk/what-do-iron-tablets-contain/
● https://www.medicines.org.uk/emc/product/4231/smpc#gref
● https://www.nhs.uk/conditions/vitamins-and-minerals/iron/
● https://practical-science.com/practical-investigations/titration-redox-iron-tablet/
Risk assessment:
● Iron powder is a flammable solid - wear eye protection to keep powder away from
eyes as it can cause irritation Student safety sheets 38 Iron and its compounds -
Cleapss
● Potassium manganate (VII) is harmful if swallowed - keep contact away from skin
and wear eye protection
https://issr.edu.kh/science/Webpage/Lab_Techniques/Edexcel%20Practical%20Che
mistry%20-%20Halesowen/Edexcel2009/pot_manganate_hazard_data.htm#:~:text=
● Aqueous sulfuric acid can use skin burns/ eye irritation - avoid contact with eyes and
skin so wear gloves and eye protection Student safety sheets 38 Iron and its
compounds - Cleapss
Equipment needed:
● Lab coat
● Safety goggles
● Gloves
● Iron tablet
● Acidified potassium manganate (VII) solution - approximately 0.0100 mol dm⁻³
● Aqueous sulfuric acid - 1.00 mol dm⁻³
● Distilled water
● 25 ml volumetric flask
● 50 ml burette
● Measuring cylinder
● Conical flask
● Glass rod
● Scale
● Mortar and pestle
● Waste container
Method:
1. Using a mortar and pestle, crush the iron tablet into a fine powder.
2. Weigh out a sample of approximately 0.1-.0.2 g of the iron tablet powder using a
scale (make sure to tear it beforehand).
3. Transfer weighed powder into a 25 ml volumetric flask.
4. Using a measuring cylinder, get 10 ml of 1 mol dm⁻³ sulfuric acid and add it in the
volumetric flask, swirl to dissolve the iron tablet powder.
5. Pour distilled water into the same volumetric flask up to the 25 ml mark to dilute the
solution.
6. Transfer this solution to a conical flask.
7. Fill up the burette with the potassium manganate (VII) solution.
8. Very slowly add the potassium manganate (VII) solution whilst stirring with a glass
rod.
9. As the potassium manganate (VII) solution is being added to the iron, it oxidises it
and the solution should turn from purple to a pale pink which indicates that all of the
iron has reacted with the KMnO4.
10.Record the volume of potassium manganate (VII) solution used to reach the
endpoint.
11.To ensure the reliability of the titration, repeat steps 6-10 another 2 times.
12.Calculate a mean volume of potassium manganate (VII) solution, using the data from
the previous step, used to reach the endpoint.
13.The mean value can then be used to calculate the exact mass of iron in the tablet.
14.Dispose of any waste solution according to institutions guidelines.
Equipment and method:
https://practical-science.com/2023/03/16/redox-iron-tablet-titration-improved/
