Lecture Notes: Solubility of Salts

Soluble Salts

• Sodium Chloride: Known to be soluble in water.
• Copper Sulfate: Also soluble, forms a solution in water.
• Potassium Chloride: Important for nerve conduction, facilitating chemical message relay.

Determining Solubility

• Solubility can be determined by:
  • Chemical Formula
  • Constituent Ions

Solubility Rules

• Nitrates: All are soluble.
• Chlorides, Bromides, Iodides: Soluble except for lead and silver.
  • Silver Halides: Used to test for halides due to insolubility.
  • Distinction among silver halides is possible due to characteristic colors and behavior in ammonia.
• Sulfates: Soluble except lead, barium, and calcium.
  • Barium Sulfate: Insoluble and radio-opaque, used in x-rays.
• Carbonates: Insoluble except sodium, potassium, ammonium.
• Hydroxides: Insoluble except sodium, potassium, ammonium.
• Sodium, Potassium, Ammonium Salts: All soluble.
• Calcium Hydroxide: Mildly soluble, lime water used to test for CO2.

Examples of Solubility

• Calcium Carbonate, Magnesium Hydroxide: Insoluble.
• Potassium Iodide, Lithium Nitrate: Soluble.
• Lead Bromide: Insoluble.

Use of Solubility Table

• Purpose: Compile solubility rules for practical use.
• Importance: Avoid complications with toxic ions, e.g., using barium sulfate instead of barium chloride.

Hard Water

• Definition: Contains calcium and magnesium ions.
• Problems: Forms insoluble salts like limescale, prevents soap lathering.
• Treatment: Ion exchange with sodium and potassium ions to soften water.

Conclusion

• Solubility rules help determine the solubility of salts, important for applications in chemistry and daily life.