Acids and Bases: In-Depth Notes

• Arrhenius Definition:

  • Acid: Increases hydrogen ion concentration (H⁺ or H₃O⁺) in water.

  • Base: Increases hydroxide ion concentration (OH⁻) in water.

• Brønsted-Lowry Definition:

  • Acid: Proton donor.

  • Base: Proton acceptor.

• Salts: Dissociate in solution without releasing H⁺ or OH⁻; e.g., KCl → K⁺ + Cl⁻.

Water's Role with Acids

• Water acts as a Brønsted–Lowry base, forming hydronium ion (H₃O⁺) when an acid dissolves.

• Example:
  H₂O + HCl → H₃O⁺ + Cl⁻

Properties of Acids

• Taste: Sour.

• Reactivity: React with metals to produce H₂ gas.

• Electrolytes: Conduct electricity.

• Neutralization: Forms salt and water; e.g.,
  HCl + NaOH → NaCl + H₂O

• pH Level: < 7.

Examples of Acids

• Strong: HCl, HNO₃, H₂SO₄, HBr, HClO₄.

• Weak: HC₂H₃O₂, H₃PO₄.

Properties of Bases

• Taste: Bitter.

• Texture: Slippery.

• Electrolytes: Conduct electricity.

• Neutralization: Forms salt and water.

• pH Level: > 7.

Examples of Bases

• NaOH, KOH, Mg(OH)₂, Ca(OH)₂.

Acid and Base Reactions

• Neutralization Reaction:
  Acid + Base → Salt + Water

pH Scale

• Definition: Concentration measure of H₃O⁺.

• Scale Range: 0 (acidic) to 14 (basic); neutral = 7.

Common Uses

• H₃PO₄: Soft drinks, fertilizers.

• H₂SO₄: Fertilizers, car batteries.

• HCl: Gastric juice.

• HC₂H₃O₂: Vinegar.

• NaOH: Drain cleaner, oven cleaner.

• Mg(OH)₂: Antacid, laxative.

• NH₃: Cleaners, fertilizers (weak base).