7.2.4—Strong acids and strong bases as fully

A strong acid dissociates almost completely in water; a strong base reacts or dissociates to produce hydroxide essentially completely. Weak acids and bases establish an equilibrium with substantial undissociated species.

Strength is an equilibrium property, not a measure of how much solution is present. A dilute strong acid can have lower concentration than a concentrated weak acid while still being more completely ionised.

HCl is strong, so [H₃O⁺] is close to its analytical concentration. Ethanoic acid is weak, so only part of CH₃COOH ionises and CH₃COOH ⇌ H⁺ + CH₃COO⁻ must be considered.

Do not use pH alone to label strength without knowing concentration. Concentration and degree of ionisation are separate ideas.