Acid-base theory

Science

Definition

Acid-base theory encompasses multiple models for defining acids and bases. The Arrhenius model defines acids as H⁺ donors and bases as OH⁻ donors in water. The Brønsted-Lowry model defines acids as proton (H⁺) donors and bases as proton acceptors. The Lewis model defines acids as electron-pair acceptors and bases as electron-pair donors.

Examples

  • HCl is an Arrhenius acid because it dissociates to produce H⁺ ions in water
  • NH₃ is a Brønsted-Lowry base because it accepts a proton from water to form NH₄⁺
  • BF₃ is a Lewis acid because it accepts an electron pair from NH₃ in a coordinate bond
Key Fact

Arrhenius ⊂ Brønsted-Lowry ⊂ Lewis; each successive model is broader in scope.

Study This Concept

Practice acid-base theory with free review games in these units: