Dissociation

Summary: The process by which an acid or base splits into its ions when dissolved in water. Tags: igcse chemistry definition acids-bases Created: 2026-07-14 Last Updated: 2026-07-14

Dissociation (also called ionisation at IGCSE) is the process by which an acid or base separates into its constituent ions when dissolved in water.

Strong acid dissociation (complete): HCl(aq) → H⁺(aq) + Cl⁻(aq) — uses single arrow (→)

Weak acid dissociation (partial, equilibrium): CH₃COOH(aq) ⇌ H⁺(aq) + CH₃COO⁻(aq) — uses equilibrium arrow (⇌)

Strong base dissociation: NaOH(s) → Na⁺(aq) + OH⁻(aq)

Key point: The degree of dissociation determines whether an acid/base is strong or weak. A strong acid has a higher degree of dissociation at any given concentration.

See also: Strong Acid, Weak Acid, Acids and Bases, Equilibrium

This is a key term definition page — part of the IGCSE Chemistry (0620/0971) keyword glossary.