Neutralisation Reactions and Their Equations

Neutralisation Reactions

  • Neutralisation Reaction Overview:
    • General form: Acid + Base → Salt + Water

Example 1: Hydrochloric Acid and Sodium Hydroxide

  • Molecular Equation:

    • Aqueous Hydrochloric Acid (HCl) + Aqueous Sodium Hydroxide (NaOH) → Water (H₂O) + Sodium Chloride (NaCl)

  • Complete Ionic Equation:

    • HCl → H⁺ + Cl⁻
    • NaOH → Na⁺ + OH⁻
    • Products: H₂O + Na⁺ + Cl⁻ (Spectator ions present)

  • Net Ionic Equation:

    • H⁺ + OH⁻ → H₂O (liquid)
    • Balance Check: 2 H on both sides, 1 O on both sides.

  • Key Concept:

    • Spectator Ions: Na⁺ and Cl⁻ not involved in the reaction.
    • This net ionic equation applies to all acid-base reactions.

Example 2: Sulfuric Acid and Lithium Hydroxide

  • Molecular Equation:

    • Aqueous Sulfuric Acid (H₂SO₄) + Aqueous Lithium Hydroxide (LiOH) → Water + Lithium Sulfate (Li₂SO₄)

  • Balancing the Equation:

    • Coefficients needed:
    • 2 LiOH → 2 Li²⁺ and
    • 2 H₂O results
    • Balanced Equation:
    • H₂SO₄ + 2 LiOH → 2 H₂O + Li₂SO₄

  • Key Concept:

    • Lithium sulfate has a formula Li₂SO₄ due to (SO₄)²⁻ needing two Li⁺ ions for neutralisation.

Example 3: Hydrobromic Acid and Sodium Hydrogen Carbonate

  • Molecular Equation:

    • Aqueous Hydrobromic Acid (HBr) + Aqueous Sodium Hydrogen Carbonate (NaHCO₃) → Water + Sodium Bromide (NaBr) + Carbon Dioxide (CO₂)

  • Products:

    • Water (H₂O), Sodium Bromide (NaBr), and Carbon Dioxide (CO₂)

  • Balance Check:

    • H: 2 on both sides, Br: 1 on both sides, Na: 1 on both sides, and CO₂ produced balances the equation.

  • Key Concept:

    • When reacting an acid with a carbonate or hydrogen carbonate, CO₂ is produced along with salt and water.

Summary of Key Concepts

  • Two types of neutralisation reactions:
    • Standard (Acid + Base = Salt + Water)
    • Carbonate/Hydrogen Carbonate (Acid + Carbonate/Hydrogen Carbonate = Salt + Water + CO₂)
  • Important Terms:
    • Reactants: Substances undergoing the reaction.
    • Products: New substances formed in the reaction.
    • Spectator Ions: Ions that do not participate in the actual chemical reaction and remain unchanged in solution.