Lecture Notes on Inorganic Compounds: Oxides, Hydroxides, and Acids

Introduction

• Presenter: Andre from Med School EU
• Topic: Inorganic Compounds based on IMAT specifications
• Focus: Properties of Oxides, Hydroxides, and Acids

Oxides

• Defined as chemical compounds with one or more oxygen atoms.
• Typically binary compounds (two different elements: metal/non-metal + oxygen).
• Examples:
  • Lithium Oxide (Li₂O)
  • Carbon Dioxide (CO₂)
  • Sulfur Dioxide (SO₂)
  • Calcium Oxide (CaO)
  • Water (H₂O)

Properties of Oxides

1. Acidic Oxides (Acid Anhydrides):

   • Non-metal oxide + water → Acid
   • Example: SO₂ + H₂O → H₂SO₃ (Sulfurous Acid)
   • Reaction with base (e.g., NaOH) forms salt and water.

2. Basic Oxides (Base Anhydrides):

   • Metal oxide + water → Base
   • Example: MgO + H₂O → Mg(OH)₂
   • Typically from alkali and alkaline earth metals.
   • Reaction with acid forms salt and water.

3. Amphoteric Oxides:

   • Can react as an acid or a base.
   • Understanding requires knowing acid-base definitions.

Acid and Base Definitions

1. Arrhenius Definition:

   • Acid: Produces H₃O⁺ in aqueous solution.
   • Base: Produces OH⁻ in aqueous solution.

2. Brønsted-Lowry Definition:

   • Acid: Proton donor.
   • Base: Proton acceptor.

Amphoteric Oxides

• Can function both as an acid and a base.
• Example reactions:
  • HCl + H₂O → H₃O⁺ + Cl⁻ (H₂O acts as base)
  • NH₃ + H₂O → NH₄⁺ + OH⁻ (H₂O acts as acid)

Hydroxides

• Hydroxide (OH⁻) ions form strong bases, especially with alkali metals.
• Strong Bases Examples:
  • NaOH, LiOH, KOH
• Properties:
  • Taste bitter.
  • Feel slippery (e.g., detergent).
  • Neutralize acids.

Properties of Acids

• Form hydronium (H₃O⁺) and proton ions.
• Taste sour.
• Dissolve metals, releasing H₂ gas.
• Neutralize bases.

pH Concept

• Measures concentration of H⁺ ions in solution.
• Scale:
  • Closer to 0 → Stronger acid
  • Closer to 14 → Stronger base
  • pH 7 → Neutral
• Example of Neutral Compound: Purified water at pH 7.

Conclusion

• Covered properties and examples of oxides, hydroxides, and acids.
• Importance of understanding acid-base reactions and pH as it relates to compound behavior.