How Ferrous Sulphate Contributes to Plant Health and Soil Quality

Ferrous sulphate, also known as iron(II) sulphate, is an iron salt with the chemical formula FeSO4​. It is most commonly found in its hydrated form as ferrous sulphate heptahydrate FeSO4⋅7H2O which appears as blue-green crystals.

Chemical Properties

1. Molecular Formula: FeSO4\text{FeSO}_4FeSO4​
2. Molar Mass:
   • Anhydrous: 151.91 g/mol
   • Heptahydrate: 278.01 g/mol
3. Appearance:
   • Anhydrous: White powder
   • Heptahydrate: Blue-green crystals
4. Solubility: Soluble in water, forming a pale green solution.
5. Melting Point:
   • Anhydrous: Decomposes at 680 °C
   • Heptahydrate: Decomposes at 64 °C
6. Density:
   • Anhydrous: 3.65 g/cm³
   • Heptahydrate: 1.898 g/cm³
7. pH: Aqueous solutions are acidic, typically around pH 3.5-4.5.

Chemical Reactions

1. Hydration and Dehydration:
   • Hydrated ferrous sulphate can lose water molecules upon heating, transitioning to less hydrated forms and eventually to anhydrous ferrous sulphate.
2. Oxidation:
   • Ferrous sulphate can oxidize to ferric sulphate (Fe2(SO4)3\text{Fe}_2(\text{SO}_4)_3Fe2​(SO4​)3​) in the presence of oxygen.
   4FeSO4+O2+2H2SO4→2Fe2(SO4)3+2H2O4\text{FeSO}_4 + \text{O}_2 + 2\text{H}_2\text{SO}_4 \rightarrow 2\text{Fe}_2(\text{SO}_4)_3 + 2\text{H}_2\text{O}4FeSO4​+O2​+2H2​SO4​→2Fe2​(SO4​)3​+2H2​O

Usage in Day-to-Day Life

1. Medical Use:
   • Iron Supplement: Ferrous sulphate is widely used as an iron supplement to treat iron-deficiency anemia. It increases the levels of iron in the blood, which is essential for the formation of red blood cells.
2. Water Treatment:
   • Coagulant: It is used in water and wastewater treatment processes as a coagulant to remove impurities by causing them to clump together for easier removal.
3. Agriculture:
   • Soil Amendment: Ferrous sulphate is used to correct iron chlorosis (yellowing of leaves due to iron deficiency) in plants. It helps in maintaining the green color of plants and is often applied to the soil or foliage.
4. Fertilizers:
   • Nutrient Source: It is included in fertilizers to provide a source of iron, which is an essential micronutrient for plant growth.
5. Industry:
   • Pigment Production: It is used in the manufacture of iron-based pigments for paints and coatings.
   • Dyeing: Employed as a mordant in the dyeing process to fix dyes to fabrics.
   • Cement Industry: Used as a reducing agent in the production of Portland cement.
6. Household Use:
   • Moss Killer: Often used in lawn care products to control moss growth in lawns.
   • Rust Removal: Utilized in some cleaning products for rust removal due to its iron content.

Safety and Handling

• Toxicity: Ferrous sulphate can be toxic if ingested in large quantities. It is particularly dangerous for children and should be stored out of their reach.
• Handling: Protective gloves and eyewear should be worn when handling ferrous sulphate to avoid irritation to the skin and eyes.
• Storage: It should be stored in a cool, dry place away from moisture to prevent it from forming hydrates or oxidizing.

Ferrous sulphate is a versatile compound with numerous applications in various fields due to its chemical properties and relatively low cost.