Solution Lecture Notes

Introduction to Solution

• Solution: Homogeneous mixture

  • Important: Always homogeneous, never heterogeneous.
  • Solute completely soluble in solvent.

• Components of Solution:

  • Major components:
    • Solvent: Usually more in quantity.
    • Solute: Lesser quantity, dissolves in solvent.

Examples

• Tea Example:
  • Milk (solvent), Sugar (solute), Salt (additional solute).
  • Binary Solution: One solvent, one solute.
  • Ternary Solution: One solvent, two solutes.
  • Quaternary Solution: One solvent, more than two solutes.

Types of Solutions

• Binary Solution: Two components (one solvent, one solute).
• Ternary Solution: One solvent, two solutes.
• Quaternary Solution: One solvent, more than two solutes.
• Solvent: Always one, solutes can be more than one.

Concentration of Solutions

• Concentration: Amount of solute in a given volume of solution.
• Different ways to express concentration:
  • Molarity (M): Moles of solute per liter of solution.
  • Molality (m): Moles of solute per kg of solvent.
  • Mass by Volume Percentage: Mass of solute (g)/Volume of solution (ml) × 100.
  • Mass by Mass Percentage: Mass of solute (g)/Mass of solution (g) × 100.
  • Volume by Volume Percentage: Volume of solute (ml)/Volume of solution (ml) × 100.
  • Mole Fraction: Moles of a component / Total moles.
  • Parts per Million (PPM): Mass of solute (g)/Mass of solution (g) × 10^6.

Vapour Pressure

• Vapor Pressure: Maximum pressure exerted by vapor at equilibrium.
• Depends only on temperature and nature of the liquid.
• Raoult’s Law: Total vapor pressure is sum of partial pressures of components.

Colligative Properties

• Depend only on the number of solute particles, not on their nature.
• Lowering of Vapor Pressure: Decrease in vapor pressure due to solute.
  • Delta P = PA0 × XB

Boiling Point Elevation

• Increase in boiling point of a solvent upon addition of solute.
• Delta TB = KB × Molality

Freezing Point Depression

• Decrease in freezing point of a solvent upon addition of solute.
• Delta TF = KF × Molality

Osmotic Pressure

• Pressure required to stop the flow of solvent into solution through a semi-permeable membrane.
• Pi = CRT
• Reverse Osmosis: Movement from solution to solvent side by applying pressure greater than osmotic pressure.

Special Cases

• Isotonic Solutions: Same osmotic pressure.

These notes summarize the key concepts and examples from the lecture on solutions, focusing on definitions, properties, and examples for understanding solutions in chemistry.