Ferrous Sulfate (FeSO₄)

Preparation of Ferrous Sulfate:

• Ferrous sulfate can be prepared by:
  • Reacting iron metal with dilute sulfuric acid:
    • Fe + H2SO4 → FeSO4 + H2
  • Reacting ferrous oxide with sulfuric acid:
    • FeO + H2SO4 → FeSO4 + H2O
  • Reacting ferrous hydroxide with sulfuric acid:
    • Fe(OH)2 + H2SO4 → FeSO4 + 2H2O

Properties of Ferrous Sulfate:

• Physical Appearance: Greenish-white crystalline solid when hydrated (FeSO₄·7H₂O) and a white powder when anhydrous (FeSO₄).
• Solubility: Soluble in water, with a slightly acidic taste.
• Nature: Ionic compound.
• Melting Point: 70°C (158°F) for the heptahydrate form.
• Chemical Nature: Oxidizing agent, reactive with reducing agents.

Uses

1. Dietary Supplement: Used to treat iron-deficiency anemia.
2. Agriculture: Serves as a fertilizer to correct iron deficiencies in plants.
3. Water Treatment: Used for phosphate removal and as a coagulant.
4. Manufacturing: Employed in the production of inks, wood preservatives, and other chemicals.

Storage

• Store in a cool, dry place, away from heat and direct sunlight.
• Keep in a tightly closed container to minimize exposure to air and moisture.
• Store away from strong oxidizing agents and reducing agents to prevent chemical reactions.

Assay

• Method: Redox titration using potassium permanganate (KMnO₄).

• Procedure:

  1. Prepare a standard KMnO₄ solution of known concentration.
  2. Weigh a sample of ferrous sulfate and dissolve it in distilled water, adding a small amount of sulfuric acid.
  3. Heat the solution to 60-70°C to ensure a faster reaction.
  4. Titrate the ferrous sulfate solution with the KMnO₄ solution.
  5. The reaction forms ferric sulfate (Fe₂(SO₄)₃) and manganese(II) sulfate (MnSO₄).
  6. Continue until a pale pink color persists, indicating the endpoint.
  7. Calculate the concentration of ferrous sulphate using the volume of titrant and the concentration of KMnO₄

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