General Information:

• • Group: V
  • Period: 3
  • Atomic Number: 15
  • Electron Configuration: 2.8.5
  • Valency: 3 (also exhibits 5)
• Sources:
  • Bones
  • Banana peels
  • Composite farm manure
  • Crab shells
  • Eggs
  • Earth’s crust (as phosphates)
  • Mineral rocks (mainly phosphates)
• Physical Properties:
  • Yellow solid at room temperature
  • Does not conduct heat or electricity
  • Two allotropes: white and red phosphorus
  • Insoluble in water
  • Melting Point: 44ºC; Boiling Point: 280ºC
• Chemical Properties:
  • Reacts with oxygen to form oxides (e.g., phosphorus pentoxide, phosphorus trioxide)
  • Combines easily with halogens
  • Reacts with metals

Allotropes of Phosphorus

1. White Phosphorus (P₄):
   • Structure: Exists as tetrahedral P₄ molecules.
   • Properties:
     • Highly reactive and can ignite in air.
     • Emits a faint glow in the dark (phosphorescent).
     • Toxic and can cause severe burns.
2. Red Phosphorus:
   • Structure: Amorphous network of phosphorus atoms.
   • Properties:
     • More stable and less reactive than white phosphorus.
     • Does not glow in the dark.
     • Used in safety matches, fireworks, and in the production of certain chemicals.

Uses of Phosphorus

• Manufacture of inorganic fertilizers (e.g., ammonium phosphate)
• Production of phosphoric acid
• Manufacture of matches
• Production of toothpaste, detergents, and baking powder

Uses of Phosphoric Acid in Inorganic Fertilizers and Food Additives

1. Inorganic Fertilizers

Phosphoric Acid and Fertilizers

• Phosphoric acid is important for making fertilizers that help plants grow. Here are some common fertilizers made with it:

1. Triple Superphosphate (TSP):
   • What it is: A fertilizer high in phosphorus.
   • How it’s made: When phosphoric acid reacts with phosphate rock.
   • Why it’s used: It provides plants with the phosphorus they need for strong root growth.
2. Monoammonium Phosphate (MAP):
   • What it is: A fertilizer that contains both nitrogen and phosphorus.
   • How it’s made: By combining phosphoric acid with ammonia.
   • Why it’s used: It helps plants grow by giving them essential nutrients.
3. Diammonium Phosphate (DAP):
   • What it is: Another fertilizer that supplies nitrogen and phosphorus.
   • How it’s made: When phosphoric acid reacts with more ammonia.
   • Why it’s used: It promotes healthy plant development and higher yields.

Benefits of Phosphoric Acid in Fertilizers:

• It makes phosphorus more available for plants, helping them absorb nutrients better.

2. Food Additives

Phosphoric Acid in Food

• Phosphoric acid is also used in many foods and drinks. Here’s how:

1. Acidulant:
   • What it is: A substance that adds acidity to foods.
   • Why it’s used: It enhances flavor, making food taste better.
2. Preservative:
   • What it does: Prevents the growth of harmful bacteria in foods.
   • Why it’s used: It helps keep food safe and fresh for longer.
3. Nutritional Supplement:
   • What it provides: A source of phosphorus, which is essential for health.
   • Why it’s used: It helps meet dietary needs.
4. In Carbonated Drinks:
   • What it does: Adds a tangy flavor to soft drinks.
   • Why it’s used: It balances sweetness, making drinks more enjoyable.
5. Processing Agent:
   • What it does: Improves the texture and stability of foods like cheese.
   • Why it’s used: It helps in creating high-quality food products.