Understanding Acids, Bases, and Alkalis

Acids

• Common acids: Hydrochloric acid (HCl), Sulfuric acid, Nitric acid.
• Aqueous Solutions: Indicated by "aq" (dissolved in water).
• Key Factor: Acids produce hydrogen ions (H⁺) in aqueous solutions.
  • Example: Hydrochloric acid releases H⁺ and Chloride ions (Cl⁻).
  • Sulfuric acid produces H⁺ and Sulfate ions (SO₄²⁻).
  • Nitric acid produces H⁺ and Nitrate ions (NO₃⁻).

Bases and Alkalis

• Bases: Chemicals that can neutralize acids, producing a salt and water.
  • Common bases: Copper oxide, Iron(III) hydroxide, Sodium hydroxide.
  • Usually metal oxides or metal hydroxides.
• Alkalis: Bases that are soluble in water.
  • Sodium hydroxide is both a base and an alkali.
• Key Factor: Alkalis produce hydroxide ions (OH⁻) in aqueous solution.
  • Example: Sodium hydroxide produces Sodium ions (Na⁺) and Hydroxide ions (OH⁻).

The pH Scale

• Measures acidity or alkalinity of a solution.
• Values:
  • Acids: pH 0 to 6.
  • Neutral: pH 7.
  • Alkalis: pH 8 to 14.
• Determining pH:
  • pH probe: Provides electronic measurement.
  • Universal indicator: Changes color based on pH.
    • Green: Neutral (pH 7).
    • Red: Very acidic.
    • Purple: Very alkaline.

Neutralization Reaction

• Reaction: Acid (H⁺ ions) + Alkali (OH⁻ ions) → Water.
• Equation: H⁺ + OH⁻ → H₂O.

Additional Resources

• For more practice, refer to the workbook available through freesciencelessons.co.uk.