Lecture on Solutions

Introduction to Solutions

• Solutions are homogeneous mixtures of two or more substances.
• Solvent: The substance present in greater amount.
• Solute: The substance(s) present in lesser amount.

Examples of Solutions

• Salt Water: Ocean water is a solution where salt is dissolved in water.
• Solutions can consist of different phases:
  • Solid in Liquid: Example - Sugar dissolved in water.
  • Solid in Solid: Example - Alloys (e.g., nickel in copper in pennies).
  • Gases in Gases: Earth's atmosphere is a solution of gases.

Dissolving Process

• Aqueous Solutions: When a solid like sugar dissolves in water, it is termed as 'aqueous'.
• Covalent Compounds:
  • Example: Sugar (sucrose) dissolves in water and is evenly distributed.
• Ionic Compounds:
  • They not only dissolve but also dissociate into ions.
  • Example: Potassium dichromate dissociates into potassium ions and dichromate ions to interact with water molecules.

Characteristics of Solutions

• Homogeneous Mixtures: Components are evenly distributed.
• Phase of Solvent: The solution exists in the phase of the solvent (e.g., gas dissolved in liquid results in a liquid solution).
• Molecular Scale Dispersion: Solute particles remain dispersed evenly and do not settle.

Key Points

• Solutions can include solids, liquids, and gases as solutes or solvents.
• Understanding the dissolution and dissociation processes is crucial for defining solution properties.

This lecture provides a foundational understanding of what solutions are, how they are formed, and their various types and characteristics.